OFFSET
1,1
COMMENTS
LINKS
Robert Israel, Table of n, a(n) for n = 1..368
EXAMPLE
a(1) = 3 + 3 + 3 + 3 + 7 = 19.
a(2) = 3 + 3 + 3 + 7 + 7 = 23.
a(3) = 3 + 7 + 7 + 7 + 7 = 31.
MAPLE
N:= 10^10: # to get all terms <= N
for n from 1 while numtheory:-mersenne([n]) < N do od:
S:= {seq(numtheory:-mersenne([i]), i=1..n-1)}:
sort(select(t -> (t <= N and isprime(t)), convert(
{seq(seq(seq(seq(seq(S[i]+S[j]+S[k]+S[l]+S[m],
m=1..l), l=1..k), k=1..j), j=1..i), i=1..n-1)}, list)));
MATHEMATICA
s = {3, 7, 31, 127, 8191, 131071, 524287} (* A000668 *); Take[Union@ Flatten@ Table[p = s[[a]] + s[[b]] + s[[c]] + s[[d]] + s[[e]]; If[ PrimeQ@ p, p, Sequence @@ {}], {e, 7}, {d, e}, {c, d}, {b, c}, {a, b}], 50] (* Robert G. Wilson v, Mar 02 2016 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Robert Israel, Mar 02 2016
STATUS
approved