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.

A350865 Sum of the larger parts in the partitions of n into two prime parts.

Original entry on oeis.org

0, 0, 0, 0, 2, 3, 3, 5, 5, 7, 12, 0, 7, 11, 18, 13, 24, 0, 24, 17, 30, 19, 47, 0, 49, 23, 55, 0, 40, 0, 59, 29, 48, 31, 100, 0, 102, 0, 50, 37, 89, 0, 120, 41, 109, 43, 136, 0, 181, 47, 158, 0, 117, 0, 199, 53, 133, 0, 170, 0, 252, 59, 133, 61, 261, 0, 300, 0, 98, 67, 267, 0
Offset: 0

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Author

Wesley Ivan Hurt, Jan 19 2022

Keywords

Examples

			a(10) = 12; The partitions of 10 into two prime parts are (7,3) and (5,5). The sum of the larger parts of these partitions is then 7+5 = 12.
		

Crossrefs

Cf. A010051, A061358, A339399, A350866, A350883 (smaller parts).

Programs

  • PARI
    a(n) = sum(k=1, n\2, if (isprime(k) && isprime(n-k), n-k)); \\ Michel Marcus, Jan 21 2022

Formula

a(n) = Sum_{k=1..floor(n/2)} c(k) * c(n-k) * (n-k), where c = A010051.
a(n) = Sum_{k=floor((n-1)^2/4)+1..floor(n^2/4)} c(2k-1) * c(2k) * A339399(2k), where c = A350866.