OFFSET
1,4
LINKS
Michael De Vlieger, Table of n, a(n) for n = 1..10000
FORMULA
EXAMPLE
MATHEMATICA
Array[#/2^IntegerExponent[#, 2] &[Times @@ FactorInteger[Prime[#] - 1][[All, 1]]] &, 72] (* Michael De Vlieger, Aug 09 2022 *)
PROG
(PARI) a(n) = factorback(setminus(factorint(prime(n)-1)[, 1]~, [2]))
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Jianing Song, Aug 09 2022
STATUS
approved