A079361 Primes in the sequence of sums of alternating powers of 2.

5, 7, 19, 43, 379, 1531, 3067, 24571, 98299, 100663291, 6442450939, 51539607547, 844424930131963, 13510798882111483, 55340232221128654843, 1947111321950560360698936123457531, 133804471191183738849214309635890169035882491

Offset: 1

Author

Cino Hilliard, Feb 15 2003

Keywords

• nonn

Comments

Sum of reciprocals = 0.4224131591021966740339033736...

Primes in A079360. - R. J. Mathar, Dec 03 2014

Links

• Amiram Eldar, Table of n, a(n) for n = 1..29

Crossrefs

Cf. A079360.

Programs

PARI

/* Primes in the sequence of sums of alternating powers of 2 */ pseq(n) = { j=a=1; p=2; sr=0; while(j<=n, a = a + 2^(p); if(isprime(a),print1(a" "); sr+=1.0/a; ); a = a+2^(p-1); if(isprime(a),print1(a" "); sr+=1.0/a; ); p+=1; j+=2; ); print(); print(sr); }

Extensions

Offset changed by Georg Fischer, Sep 02 2022

a(16)-a(17) from Amiram Eldar, Jul 06 2024