OFFSET
1,4
FORMULA
PROG
(PARI) { A255643(n) = my(r); r=0; for(i=0, n-1, if(issquare(Mod(i, n)), r+=i, r-=i) ); r }
CROSSREFS
KEYWORD
sign
AUTHOR
Max Alekseyev, Mar 01 2015
STATUS
approved