OFFSET
1,1
COMMENTS
(6n+1)*(12n+1)*(18n+1)*(36n+1)*(72n+1) is a Carmichael number for all n in this sequence.
More precisely, these products are in A112428 = A002997 intersect A014614. - M. F. Hasler, Apr 14 2015
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
Jack Chernick, On Fermat's simple theorem, Bull. Amer. Math. Soc., Volume 45, Number 4 (1939), pp. 269-274.
MATHEMATICA
Select[Range[250000], PrimeQ[6 #+1] && PrimeQ[12 #+1] && PrimeQ[18 #+1] && PrimeQ[36 #+1] && PrimeQ[72 #+1] && Mod[#, 2] == 0&]
PROG
(PARI) is_A206349(n, c=72)=!bittest(n, 0)&&!until(bittest(c\=2, 0)&&9>c+=3, isprime(n*c+1)||return) \\ M. F. Hasler, Apr 14 2015
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
José María Grau Ribas, Feb 06 2012
STATUS
approved