OFFSET
1,5
LINKS
PROG
(PARI)
A000265(n) = (n>>valuation(n, 2));
A253553(n) = if(n<=2, 1, my(f=factor(n), k=#f~); if(f[k, 2]>1, f[k, 2]--, f[k, 1] = precprime(f[k, 1]-1)); factorback(f));
CROSSREFS
Cf. also A347879.
KEYWORD
nonn
AUTHOR
Antti Karttunen, Aug 03 2022
STATUS
approved