A108797 -id:A108797 - cp's OEIS frontend

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

Washington Bomfim, Feb 25 2012

nonn

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

Cf. A001567, A055550, A108797, A225005

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

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

A225005 Number of Carmichael numbers (A002997) less than 2^n.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 3, 5, 6, 9, 10, 15, 19, 23, 33, 45, 55, 69, 95, 130, 162, 214, 290, 375, 483, 656, 864, 1118, 1446, 1874, 2437, 3130, 4058, 5188, 6642, 8521, 11002, 14236, 18400, 23631, 30521, 39376, 50685, 65590, 84817, 109857, 141892, 183507, 237217, 307278, 398506, 517446, 672105, 873109, 1136472, 1479525, 1927138, 2513234, 3278553, 4279356

Offset: 1

Max Alekseyev, Apr 23 2013

nonn

Amiram Eldar, Table of n, a(n) for n = 1..73 (terms 65..69 added using A182490; terms 70..73 calculated using data from Claude Goutier)
Jan Feitsma, The pseudoprimes below 2^64 - statistics. [Wayback Machine link]
Jan Feitsma and William Galway, Tables of pseudoprimes and related data.
Claude Goutier, Compressed text file carm10e22.gz containing all the Carmichael numbers up to 10^22.

Cf. A002997, A055553, A208276, A108797.

Partial sums of A182490.

A329237 The number of base-2 Euler-Jacobi pseudoprimes (A047713) less than 2^n.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 5, 8, 10, 15, 20, 29, 42, 57, 81, 118, 179, 246, 348, 481, 654, 893, 1231, 1642, 2188, 3003, 4033, 5367, 7252, 9681, 12961, 17460, 23351, 31224, 41623, 55455, 74124, 99127, 132426, 176466, 235792, 314338, 420106, 562476, 751769, 1006184

Offset: 1

Amiram Eldar, Nov 08 2019

nonn

			Below 2^10 = 1024 there is only one Euler-Jacobi pseudoprime, 561. Therefore a(10) = 1.

Amiram Eldar, Table of n, a(n) for n = 1..64
Jan Feitsma and William F. Galway, Tables of pseudoprimes and related data.

Cf. A047713, A055551, A108797, A208276.

ejpspQ[n_] := CompositeQ[n] && PowerMod[2, (n - 1)/2, n] == Mod[JacobiSymbol[2, n], n]; s = {}; c = 0; p = 2; n = 1; Do[If[ejpspQ[n], c++]; If[n > p, AppendTo[s, c]; p *= 2], {n, 1, 2^20 + 1, 2}]; s

cp's OEIS Frontend

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

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A225005 Number of Carmichael numbers (A002997) less than 2^n.

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A329237 The number of base-2 Euler-Jacobi pseudoprimes (A047713) less than 2^n.

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Mathematica