cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A366851 Irregular triangle read by rows where T(n,k) is the number of integer partitions of n such that the sum of primes indexed by all parts greater than one is k.

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%I A366851 #7 Nov 07 2023 08:24:58
%S A366851 1,1,1,0,0,1,1,0,0,1,0,1,1,0,0,1,0,1,1,1,1,0,0,1,0,1,1,1,1,0,0,1,1,0,
%T A366851 0,1,0,1,1,1,1,1,2,1,0,1,1,0,0,1,0,1,1,1,1,1,2,2,1,1,1,0,0,1,1,0,0,1,
%U A366851 0,1,1,1,1,1,2,2,2,3,2,0,2,1,0,1,1,0,0,1,0,1,1,1,1,1,2,2,2,3,3,2,2,2,2,1,1,0,0,1
%N A366851 Irregular triangle read by rows where T(n,k) is the number of integer partitions of n such that the sum of primes indexed by all parts greater than one is k.
%C A366851 To illustrate the definition, the sum of primes indexed by all parts greater than one of the partition (5,2,2,1) is prime(5) + prime(2) + prime(2) = 17.
%e A366851 Triangle begins:
%e A366851   1
%e A366851   1
%e A366851   1 0 0 1
%e A366851   1 0 0 1 0 1
%e A366851   1 0 0 1 0 1 1 1
%e A366851   1 0 0 1 0 1 1 1 1 0 0 1
%e A366851   1 0 0 1 0 1 1 1 1 1 2 1 0 1
%e A366851   1 0 0 1 0 1 1 1 1 1 2 2 1 1 1 0 0 1
%e A366851   1 0 0 1 0 1 1 1 1 1 2 2 2 3 2 0 2 1 0 1
%e A366851   1 0 0 1 0 1 1 1 1 1 2 2 2 3 3 2 2 2 2 1 1 0 0 1
%e A366851   1 0 0 1 0 1 1 1 1 1 2 2 2 3 3 3 4 4 2 3 2 0 3 1 0 0 0 0 0 1
%e A366851   1 0 0 1 0 1 1 1 1 1 2 2 2 3 3 3 4 5 4 4 3 3 3 2 3 0 1 0 0 1 0 1
%e A366851 The T(8,13) = 3 partitions are: (6,1,1), (4,2,2), (3,3,2).
%e A366851 The T(10,17) = 4 partitions are: (7,1,1,1), (5,2,2,1), (4,4,2), (4,3,3).
%t A366851 Table[Length[Select[IntegerPartitions[n], Total[Select[Prime/@#,OddQ]]==k&]], {n,0,10}, {k,0,If[n<=1,0,Prime[n]]}]
%Y A366851 Row lengths are A055670.
%Y A366851 Columns appear to converge to A099773.
%Y A366851 A bisected even version is A116598 (counts partitions by number of 1's).
%Y A366851 Counting all parts (not just > 1) gives A331416, shifted A331385.
%Y A366851 A000041 counts integer partitions, strict A000009 (also into odds).
%Y A366851 A113685 counts partitions by sum of odd parts, rank statistic A366528.
%Y A366851 A330953 counts partitions with Heinz number divisible by sum of primes.
%Y A366851 A331381 counts partitions with (product)|(sum of primes), equality A331383.
%Y A366851 Cf. A000837, A014689, A113686, A239261, A331417, A331418, A365067, A366842.
%K A366851 nonn,tabf
%O A366851 0,43
%A A366851 _Gus Wiseman_, Nov 01 2023