OFFSET
1,1
COMMENTS
a(n)=0 for n=9,29,33,34,37,38,39,41,45,49,...;
records a(n) are on the positions: 1,2,3,5,8,11,13,14,15,17,24,25,26,48,50,...
Mersenne primes a(n) = 2^n-1 are at positions 2,3,5,17,...
LINKS
Peter J. C. Moses, Table of n, a(n) for n = 1..1000
FORMULA
a(n) <= 2^n-1.
PROG
(PARI) a(n) = {my(k = 0); while(! isprime(p=sum(i=0, k, binomial(n, i))), k++; if ((k>n) && !isprime(binomial(n, k)), return (0); )); p; } \\ Michel Marcus, May 23 2015
CROSSREFS
KEYWORD
nonn
AUTHOR
Vladimir Shevelev, May 21 2015
EXTENSIONS
More terms from Peter J. C. Moses, May 21 2015
STATUS
approved