A186300 (A007521(n)+1)/2.
3, 7, 15, 19, 27, 31, 51, 55, 75, 79, 87, 91, 99, 115, 135, 139, 147, 159, 175, 187, 195, 199, 211, 231, 255, 271, 279, 307, 327, 331, 339, 351, 355, 367, 379, 387, 399, 411, 415, 427, 439, 471, 499, 507, 511, 531, 535, 547, 555, 559, 591, 607
Offset: 1
Keywords
Formula
a(n) = A186299(n)+1.