A067292 a(n)=prime(n)-n*tau(n) where tau(n) is the number of divisors of n.

1, -1, -1, -5, 1, -11, 3, -13, -4, -11, 9, -35, 15, -13, -13, -27, 25, -47, 29, -49, -11, -9, 37, -103, 22, -3, -5, -61, 51, -127, 65, -61, 5, 3, 9, -173, 83, 11, 11, -147, 97, -155, 105, -71, -73, 15, 117, -257, 80, -71, 29, -73, 135, -181, 37, -185, 41, 39, 159, -439, 161, 45, -71, -137, 53, -211, 197, -71, 71, -211

Offset

1,4

Links

Table of n, a(n) for n=1..70.

Maple

with(numtheory); A067292:=n->ithprime(n)-n*tau(n); seq(A067292(n), n=1..100); # Wesley Ivan Hurt, Nov 21 2013

Mathematica

Table[Prime[n] - n*DivisorSigma[0, n], {n, 100}] (* Wesley Ivan Hurt, Nov 21 2013 *)

Prog

(PARI) a(n) = prime(n) - n*numdiv(n); \\ Michel Marcus, Nov 21 2013

Crossrefs

Cf. A000005.

Sequence in context: A330774 A296307 A238554 * A131782 A242060 A185953

Adjacent sequences: A067289 A067290 A067291 * A067293 A067294 A067295

Keyword

easy,sign

Author

Benoit Cloitre, Feb 24 2002

Status

approved