OFFSET
1,4
LINKS
FORMULA
EXAMPLE
For n = 36, it has three square-divisors: 4 = 2^(2*1), 9 = 3^(2*1) and 36 = 6^(2*1). Thus a(36) = prime(1) * prime(1) * prime(1) = 2*2*2 = 8.
For n = 64, it has three square-divisors: 4 = 2^(2*1), 16 = 2^(2*2) and 64 = 2^(2*3). Thus a(64) = prime(1) * prime(2) * prime(3) = 2*3*5 = 30.
PROG
(PARI) A294874(n) = { my(m=1, e); fordiv(n, d, if(d>1, e = ispower(d); if((e>1)&&!(e%2), m *= prime(e/2)))); m; };
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Nov 11 2017
STATUS
approved