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.

A334292 Number of sets of primes less than the n-th prime whose sum is the n-th prime.

Original entry on oeis.org

0, 0, 1, 1, 0, 1, 1, 2, 4, 6, 8, 10, 13, 14, 18, 25, 34, 38, 49, 60, 66, 86, 101, 129, 177, 203, 223, 256, 277, 319, 521, 594, 723, 775, 1063, 1135, 1363, 1633, 1835, 2191, 2600, 2760, 3644, 3862, 4293, 4548, 6261, 8557, 9452, 9963, 11000, 12773, 13437, 17121, 19774, 22799
Offset: 1

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Author

Gil Broussard, Apr 21 2020

Keywords

Examples

			a(5) = 0 because 11 is the 5th prime and there are 0 sets of primes < 11 whose sum = 11.
a(9) = 4 because 23 is the 9th prime and there are 4 sets of primes < 23 whose sums = 23: 13+7+3, 13+5+3+2, 11+7+5, 11+7+3+2.
		

Crossrefs

Programs

  • PARI
    lista(nn) = {my(v, w=primes(nn)); v=Vec(prod(i=1, nn, 1+'x^w[i]) + O('x^(w[nn]+1))); for(i=1, nn, print1(v[w[i]+1]-1, ", ")); } \\ Jinyuan Wang, May 04 2020

Formula

Same generating function as A111133, but on the domain of prime numbers.
a(n) = A070215(n) - 1. - Jinyuan Wang, May 04 2020

Extensions

More terms from David A. Corneth, Apr 22 2020