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6 votes
0 answers
171 views

An inequality involving integer partitions

For integers $n\ge k\ge0$, let $p(n,k)$ denote the number of ways to write $n$ as a sum of $k$ positive integers (repetition allowed). For example, $p(6,3)=3$ since $$6=1+1+4=1+2+3=2+2+2.$$ QUESTION. ...
Zhi-Wei Sun's user avatar
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3 votes
0 answers
120 views

Sequence which is related to the binary expansion of $n$ and partition numbers

Let $p(n)$ be A000041 i.e. the number of partitions of $n$ (the partition numbers). Let $$ \ell(n)=\left\lfloor\log_2 n\right\rfloor $$ Let $\operatorname{wt}(n)$ be A000120 i.e. number of $1$'s in ...
Notamathematician's user avatar
1 vote
0 answers
100 views

Conjecture on numbers $k$ having only one partition into parts with same binary weight as a binary weight of $k$

Let $\operatorname{tr}(n)$ be A007814, number of trailing zeros in the binary representation of $n$. Also, let $\operatorname{ntr}(n)$ be A086784, number of non-trailing zeros in the binary ...
Notamathematician's user avatar
3 votes
1 answer
92 views

Partition of $(2^{n+1}+1)2^{2^{n-1}+n-1}-1$ into parts with binary weight equals $2^{n-1}+n$

Let $\operatorname{wt}(n)$ be A000120, i.e., number of $1$'s in binary expansion of $n$ (or the binary weight of $n$). Let $a(n,m)$ be the sequence of numbers $k$ such that $\operatorname{wt}(k)=m$. ...
Notamathematician's user avatar
2 votes
0 answers
137 views

Writing integers as sequences of products by 2 and integer divisions by 3

For any integer, we consider its decompositions into sequences of products by $2$ and integer division by $3$. For instance: $$ 100 = 2 \cdot 2 \cdot 2 \cdot 2 \cdot 2 \cdot 2 \cdot 2 \cdot 2 \cdot 2 \...
Matthieu Latapy's user avatar
11 votes
1 answer
864 views

Up to $10^6$: $\sigma(8n+1) \mod 4 = OEIS A001935(n) \mod 4$ (Number of partitions with no even part repeated )

Up to $10^6$: $\sigma(8n+1) \mod 4 = OEIS A001935(n) \mod 4$ A001935 Number of partitions with no even part repeated Is this true in general? It would mean relation between restricted partitions ...
joro's user avatar
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2 votes
0 answers
154 views

Equi-distribution of the parity of partitions

The integer partition function $p(n)$ has a generating function given by $$\frac1{(q)_{\infty}}=\sum_{n=0}^{\infty}p(n)q^n$$ with $(q)_{\infty}=\prod_{m=1}^{\infty}(1-q^m)$. The long-standing problem ...
T. Amdeberhan's user avatar
13 votes
0 answers
718 views

Is "OEIS A001935 Number of partitions with no even part repeated" efficiently computable $\mod 4$?

Is A001935 Number of partitions with no even part repeated efficiently computable $\mod 4$? I am interested because of this relation with sum of divisors of $8n+1$. $\sigma(8n+1) \equiv A001935(n) \...
joro's user avatar
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