OFFSET
1,4
COMMENTS
A249740 gives the corresponding largest prime.
If n belongs to A013929, then a(n)>1. - Robert G. Wilson v, Nov 16 2016
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..10000
FORMULA
MATHEMATICA
Table[If[SquareFreeQ@ n, 1, p = 2; While[! Divisible[n, p^2], p = NextPrime@ p]; p], {n, 120}] (* Michael De Vlieger, Nov 15 2016 *)
PROG
(Scheme) (define (A249739 n) (let loop ((n n) (p (A020639 n))) (cond ((= 1 n) n) ((zero? (modulo n (* p p))) p) (else (loop (/ n p) (A020639 (/ n p)))))))
(PARI) a(n) = {f = factor(n/core(n)); vsq = select(x->((x%2) == 0), f[, 2], 1); if (#vsq, f[vsq[1], 1], 1); } \\ Michel Marcus, Mar 11 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Nov 04 2014
STATUS
approved