A208276 Number of Poulet numbers (or pseudoprimes to base 2, A001567) less than 2^n.

0, 0, 0, 0, 0, 0, 0, 0, 1, 3, 8, 13, 19, 32, 45, 64, 89, 124, 175, 251, 361, 502, 693, 944, 1264, 1713, 2361, 3169, 4232, 5749, 7750, 10403, 14011, 18667, 24958, 33389, 44540, 59565, 79343, 105659, 141147, 188231, 250568, 333737, 445316, 593366, 792172, 1059097, 1416055, 1893726, 2532703, 3390284, 4540673, 6086093, 8167163, 10964612, 14731767, 19806649, 26651383, 35893886, 48374139, 65247459, 88069251, 118968378

Offset: 1

Author

Washington Bomfim, Feb 25 2012

Keywords

• nonn

Links

• Jan Feitsma, The pseudoprimes below 2^64 - statistics
• Jan Feitsma and William Galway, Tables of pseudoprimes and related data

Crossrefs

Cf. A001567, A055550, A108797, A225005

Programs

PARI

count=0;for(e=1,32,forcomposite(n=2^(e-1),2^e-1,if(n%2 && Mod(2,n)^(n-1)==1,count++)); print1(count", ")); \\ Hans Loeblich, May 15 2019

Extensions

a(50)-a(64) from Feitsma's website, added by Max Alekseyev, Apr 23 2013