A070546 a(n) = Card( k, 0<k<=n such that k is relatively prime to tau(k)=A000005(k)).

1, 1, 2, 3, 4, 4, 5, 5, 5, 5, 6, 6, 7, 7, 8, 9, 10, 10, 11, 11, 12, 12, 13, 13, 14, 14, 15, 15, 16, 16, 17, 17, 18, 18, 19, 19, 20, 20, 21, 21, 22, 22, 23, 23, 23, 23, 24, 24, 25, 25, 26, 26, 27, 27, 28, 28, 29, 29, 30, 30, 31, 31, 31, 32, 33, 33, 34, 34, 35, 35, 36, 36, 37, 37

Offset

1,3

Links

Michael De Vlieger, Table of n, a(n) for n = 1..10000

Mathematica

Accumulate[Table[Boole[CoprimeQ[n, DivisorSigma[0, n]]], {n, 1, 100}]] (* Amiram Eldar, Apr 30 2022 *)

Prog

(PARI) for(n=1, 100, print1(sum(i=1, n, if(gcd(i, numdiv(i))-1, 0, 1)), ", "))

Crossrefs

Partial sums of A322980.

Cf. A000005, A009191, A046642.

Sequence in context: A060197 A116487 A249041 * A034586 A268383 A092338

Adjacent sequences: A070543 A070544 A070545 * A070547 A070548 A070549

Keyword

easy,nonn

Author

Benoit Cloitre, May 02 2002

Status

approved