A172297 Partial sums of A002234.

2, 5, 11, 41, 116, 197, 312, 435, 684, 1046, 1430, 1892, 2404, 3155, 3977, 9289, 17044, 26575, 38954, 54776, 73661, 96632, 119637, 218363, 361381, 512404, 1179475, 2374678, 3643657, 5111420, 7125412, 9493318, 13246266

Offset

1,1

Comments

The subsequence of primes in this sequence begin: 2, 5, 11, 41, 197, 218363, 3643657.

Links

Table of n, a(n) for n=1..33.

Formula

a(n) = sum[i=1..n] {i such that the Woodall number i*2^i - 1 is prime}.

Example

a(6) = 2 + 3 + 6 + 30 + 75 + 81 = 197 is prime. a(33) = 2 + 3 + 6 + 30 + 75 + 81 + 115 + 123 + 249 + 362 + 384 + 462 + 512 + 751 + 822 + 5312 + 7755 + 9531 + 12379 + 15822 + 18885 + 22971 + 23005 + 98726 + 143018 + 151023 + 667071 + 1195203 + 1268979 + 1467763 + 2013992 + 2367906 + 3752948.

Crossrefs

Cf. A000040, A002234, A050918.

Sequence in context: A237814 A007700 A071313 * A128231 A088148 A088149

Adjacent sequences: A172294 A172295 A172296 * A172298 A172299 A172300

Keyword

hard,nonn,less

Author

Jonathan Vos Post, Jan 30 2010

Status

approved