

A271221


Smallest Fermat pseudoprime k to all bases b = 2, 3, 4, ..., n.


3



341, 1105, 1105, 1729, 1729, 29341, 29341, 29341, 29341, 29341, 29341, 162401, 162401, 162401, 162401, 252601, 252601, 252601, 252601, 252601, 252601, 252601, 252601, 252601, 252601, 252601, 252601, 252601, 252601, 252601, 252601, 252601, 252601, 252601, 251601, 252601, 252601, 252601, 252601
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OFFSET

2,1


COMMENTS

a(n) is the smallest composite k such that b^(k1) == 1 (mod (b1)k) for every b = 2, 3, 4, ..., n. For more comments, see A083876 and A300629.  Max Alekseyev and Thomas Ordowski, Apr 29 2018


LINKS

Table of n, a(n) for n=2..40.


PROG

(PARI) a(n) = forcomposite(c=1, , my(i=0); for(b=2, n, if(Mod(b, c)^(c1)==1, i++)); if(i==n1, return(c)));


CROSSREFS

Cf. A052155, A083737, A083739, A083876, A300629.
Sequence in context: A179839 A172255 A087835 * A066488 A291601 A083876
Adjacent sequences: A271218 A271219 A271220 * A271222 A271223 A271224


KEYWORD

nonn


AUTHOR

Felix FrÃ¶hlich, Apr 02 2016


EXTENSIONS

Edited by Thomas Ordowski, Apr 29 2018


STATUS

approved



