OFFSET
1,3
LINKS
FORMULA
PROG
(PARI)
A064989(n) = {my(f); f = factor(n); if((n>1 && f[1, 1]==2), f[1, 2] = 0); for (i=1, #f~, f[i, 1] = precprime(f[i, 1]-1)); factorback(f)};
A209229(n) = (n && !bitand(n, n-1));
A335426(n) = if(n<=2, n-1, if(!(n%2), if(A209229(n) && A209229(valuation(n, 2)), 0, 1+A335426(n/2)), 2*A335426(A064989(n))));
\\ Alternatively:
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jun 15 2020
STATUS
approved