A059292 a(n) = n + 2 - (number of divisors of n).

2, 2, 3, 3, 5, 4, 7, 6, 8, 8, 11, 8, 13, 12, 13, 13, 17, 14, 19, 16, 19, 20, 23, 18, 24, 24, 25, 24, 29, 24, 31, 28, 31, 32, 33, 29, 37, 36, 37, 34, 41, 36, 43, 40, 41, 44, 47, 40, 48, 46, 49, 48, 53, 48, 53, 50, 55, 56, 59, 50, 61, 60, 59, 59, 63, 60, 67

Offset

1,1

References

L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 121, see #17.

Links

Harry J. Smith, Table of n, a(n) for n = 1..5000

Formula

a(n) = n + 2 - A000005(n) = A049820(n) + 2. - Omar E. Pol, Jul 16 2009

Mathematica

Table[n + 2 - DivisorSigma[0, n], {n, 1, 100}] (* G. C. Greubel, Jan 04 2017 *)

Prog

(PARI) { for (n = 1, 5000, write("b059292.txt", n, " ", n + 2 - numdiv(n)); ) } \\ Harry J. Smith, Jun 25 2009
(Magma) [n+2-DivisorSigma(0, n): n in [1..100]]; // Vincenzo Librandi, Jan 05 2017

Crossrefs

Cf. A000005, A049820, A062968. - Omar E. Pol, Jul 16 2009

Sequence in context: A114092 A082500 A194451 * A115000 A036825 A035574

Adjacent sequences: A059289 A059290 A059291 * A059293 A059294 A059295

Keyword

nonn

Author

N. J. A. Sloane, Jan 25 2001

Status

approved