A212601 - OEIS

The OEIS is supported by the many generous donors to the OEIS Foundation.

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

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

Only 1 (mod 4) numbers have been found.

LINKS

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

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 &]

CROSSREFS

Cf. A201629.

Cf. A001567 (pseudoprimes to base 2).

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

Sequence in context: A329881 A234838 A234834 * A060896 A371757 A206617

Adjacent sequences: A212598 A212599 A212600 * A212602 A212603 A212604

KEYWORD

nonn

AUTHOR

José María Grau Ribas, May 22 2012

STATUS

approved