A108797 Number of base-2 strong pseudoprimes (A001262) less than 2^n.

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 3, 4, 6, 7, 11, 18, 24, 34, 49, 75, 104, 147, 210, 296, 409, 552, 734, 981, 1311, 1736, 2314, 3093, 4139, 5511, 7396, 9835, 13106, 17493, 23270, 31115, 41664, 55763, 74739, 100342, 134559, 180725, 243566, 327731, 441270, 594585, 803252, 1085426, 1468777, 1988905, 2697846, 3662239, 4976375, 6767707, 9212942, 12552513, 17114780, 23355139, 31894014

Offset: 1

Author

Charles R Greathouse IV, Dec 03 2005

Keywords

• nonn

Examples

			a(12)=3 since 2047, 3277 and 4033 are the 2-SPSPs less than 4096.
		

Links

• Eric Weisstein's World of Mathematics, Strong Pseudoprime
• Jan Feitsma and William Galway, Tables of pseudoprimes and related data

Crossrefs

Cf. A001262, A055552, A208276

Extensions

a(24)-a(64) from Charles R Greathouse IV, Jan 28 2011, based on the calculations of Jan Feitsma.

a(1)=...=a(10)=0 prepended by Max Alekseyev, Apr 23 2013