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A083740 Pseudoprimes to bases 3,5 and 7. 1
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified February 19 19:28 EST 2020. Contains 332047 sequences. (Running on oeis4.)