OFFSET
1,2
LINKS
Michael De Vlieger, Table of n, a(n) for n = 1..10000
MATHEMATICA
Accumulate[Table[Boole[CoprimeQ[n, DivisorSigma[1, n]]], {n, 1, 100}]] (* Amiram Eldar, Apr 30 2022 *)
PROG
(PARI) for(n=1, 100, print1(sum(i=1, n, if(gcd(i, sigma(i))-1, 0, 1)), ", "))
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Benoit Cloitre, May 02 2002
STATUS
approved