A212601 Intersection of A001567 and A212502.

4033, 6601, 8321, 15841, 25761, 29341, 41041, 46657, 75361, 115921, 162401, 172081, 252601, 294409, 314821, 332949, 401401, 410041, 488881, 530881, 552721, 642001, 721801, 873181, 934021, 1004653, 1207361, 1461241, 1876393, 1909001, 2081713, 2085301, 2113921

Offset: 1

Author

José María Grau Ribas, May 22 2012

Keywords

• nonn

Comments

Only 1 (mod 4) numbers have been found.

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A201629.

Cf. A001567 (pseudoprimes to base 2).

Cf. A212502 (pseudoprimes to base 1+2i).

Programs

Mathematica

t[n_] := Which[Mod[n, 4] == 3, n + 1, Mod[n, 4] == 1, n - 1,  True,  n]; Select[1 + Range[99000], PowerMod[2, # - 1, #] == 1 && !PrimeQ[#] && Im[PowerMod[1 + 2I, t[#], #]] == 0 &]