OFFSET
1,2
COMMENTS
a(n) = 2n if n is a prime, a(2n+2) = 2.
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..20000
PROG
(PARI) print1("1, "); for(n=2, 100, if(isprime(n), print1(2*n, ", "), print1(factor(n)[1, 1], ", "))) (Rick L. Shepherd)
(PARI) A074828(n) = if(1==n, n, if(isprime(n), 2*n, factor(n)[1, 1])); \\ Antti Karttunen, Feb 06 2019
CROSSREFS
KEYWORD
nonn
AUTHOR
Amarnath Murthy, Sep 13 2002
EXTENSIONS
More terms from Rick L. Shepherd, Jun 07 2004
Entry revised by N. J. A. Sloane, Aug 13 2006
STATUS
approved