OFFSET
1,2
COMMENTS
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..65537
FORMULA
PROG
(PARI)
A000523(n) = if(n<1, 0, #binary(n)-1);
(PARI)
up_to = 65537;
rgs_transform(invec) = { my(om = Map(), outvec = vector(length(invec)), u=1); for(i=1, length(invec), if(mapisdefined(om, invec[i]), my(pp = mapget(om, invec[i])); outvec[i] = outvec[pp] , mapput(om, invec[i], i); outvec[i] = u; u++ )); outvec; };
Aux324401(n) = if((n>2) && (isprime(n)||!bitand(n, n-1)), -(2-(n%2)), n);
\\ Equally: Aux324401(n) = if(n<=2, n, if(isprime(n), -1, if(!bitand(n, n-1), -2, n)));
v324401 = rgs_transform(vector(up_to, n, Aux324401(n)));
A324401(n) = v324401[n];
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Mar 01 2019
STATUS
approved