A174055 Sums of three Mersenne primes.

9, 13, 17, 21, 37, 41, 45, 65, 69, 93, 133, 137, 141, 161, 165, 189, 257, 261, 285, 381, 8197, 8201, 8205, 8225, 8229, 8253, 8321, 8325, 8349, 8445, 16385, 16389, 16413, 16509, 24573, 131077, 131081, 131085, 131105, 131109, 131133, 131201, 131205, 131229, 131325, 139265, 139269, 139293, 139389, 147453, 262145, 262149

Offset

1,1

Links

Robert Israel, Table of n, a(n) for n = 1..969

Formula

A000668(i) + A000668(j) + A000668(k), with integers i,j,k not necessarily distinct. The subsequence of prime sums of three Mersenne primes is A174056.

Example

a(1) = 3 + 3 + 3 = 9. a(2) = 3 + 3 + 7 = 13. a(3) = 3 + 7 + 7 = 17. a(4) = 7 + 7 + 7 = 21. a(5) = 3 + 3 + 31 = 37. a(6) = 3 + 7 + 31 = 41.

Maple

N:= 10^6: # 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(convert(select(`<=`, {seq(seq(seq(s+t+u, s=S), t=S), u=S)}, N), list)); # Robert Israel, Mar 02 2016

Crossrefs

Cf. A000668, A155877, A166484, A171251, A171252, A171253, A171254, A171255, A174056, A174057.

Sequence in context: A329388 A227062 A134441 * A273059 A188220 A211429

Adjacent sequences: A174052 A174053 A174054 * A174056 A174057 A174058

Keyword

nonn

Author

Jonathan Vos Post, Mar 06 2010

Extensions

More terms from Max Alekseyev, Oct 15 2012

Edited by Robert Israel, Mar 02 2016

Status

approved