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.

A307470 Intersection of A013917 and A013918.

Original entry on oeis.org

2, 281, 25237, 1359329, 1603597, 6706397, 8300797, 32106383, 33262057, 33312781, 37233373, 57922687, 87938423, 124285471, 143031971, 144784201, 179684179, 185763283, 186515239, 229240489, 237863777, 248536159, 280322407, 298010851, 375529801, 481405411, 488236271, 498472207
Offset: 1

Views

Author

Torlach Rush, Apr 09 2019

Keywords

Comments

For a number to be a term of this sequence it must satisfy two similar but distinct conditions:
1. The number is prime and is the sum of consecutive primes.
2. The sum of all primes up to and including the number is also a prime number.
See examples below.

Examples

			2 is a term because 2 is prime and equals Sum_{2}. This is the trivial case.
281 is a term because 281 is prime and equals Sum_{2,3,...,41,43}, also Sum_{2,3,...,41,43,47,...,277,281} = 7699 which is also prime.
		

Crossrefs

Programs

  • PARI
    listp(nn) = {my(s=0); forprime(p=2, nn, s += p; if (isprime(s), my(ss = 0); forprime(q=2, s, ss += q); if (isprime(ss), print1(s, ", "));););} \\ Michel Marcus, Apr 11 2019

Extensions

More terms from Michel Marcus, Apr 11 2019