A083740 Pseudoprimes to bases 3,5 and 7.

29341, 46657, 75361, 88831, 115921, 146611, 162401, 252601, 294409, 314821, 334153, 340561, 399001, 410041, 488881, 512461, 530881, 552721, 658801, 721801, 852841, 954271, 1024651, 1152271, 1193221, 1314631, 1461241, 1569457, 1615681

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..8702 (terms 1..77 from R. J. Mathar)

F. Richman, Primality testing with Fermat's little theorem

Formula

a(n) = n-th positive integer k(>1) such that 3^(k-1) = 1 (mod k), 5^(k-1) = 1 (mod k) and 7^(k-1) = 1 (mod k).

Intersection of A083734 and A005938. Intersection of A083735 and A005936. - R. J. Mathar, Apr 05 2011

Example

a(1)=29341 since it is the first number such that 3^(k-1) = 1 (mod k), 5^(k-1) = 1 (mod k) and 7^(k-1) = 1 (mod k).

Mathematica

Select[Range[1, 10^5, 2], CompositeQ[#] &&  PowerMod[3, #-1, #] == PowerMod[5, #-1, #] == PowerMod[7, #-1, #] == 1&]

Crossrefs

Cf. A005935, A005936, A005938, A083734, A083735.

Sequence in context: A058652 A250940 A186566 * A083739 A329538 A182133

Adjacent sequences: A083737 A083738 A083739 * A083741 A083742 A083743

Keyword

easy,nonn

Author

Serhat Sevki Dincer (sevki(AT)ug.bilkent.edu.tr), May 05 2003

Status

approved