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A083736 Pseudoprimes to bases 2,5 and 7. +0
1
561, 29341, 46657, 75361, 115921, 162401, 252601, 294409, 314821, 334153, 340561, 399001, 410041, 488881, 512461, 530881, 552721, 656601, 658801, 710533, 721801, 852841, 1024651, 1141141, 1152271, 1168513, 1193221, 1461241, 1569457, 1615681 (list; graph; listen)
OFFSET

1,1

LINKS

R. J. Mathar, Table of n, a(n) for n=1..81

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

FORMULA

a(n) = n-th positive integer k(>1) such that 2^(k-1) = 1 (mod k), 5^(k-1) = 1 (mod k) and 7^(k-1) = 1 (mod k)

EXAMPLE

a(1)=561 since it is the first number such that 2^(k-1) = 1 (mod k), 5^(k-1) = 1 (mod k) and 7^(k-1) = 1 (mod k)

PROGRAM

Assembly

CROSSREFS

Sequence in context: A110889 A063400 A141706 this_sequence A006931 A097061 A139089

Adjacent sequences: A083733 A083734 A083735 this_sequence A083737 A083738 A083739

KEYWORD

easy,nonn

AUTHOR

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

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Last modified November 25 20:09 EST 2009. Contains 167514 sequences.


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