A054006 Number of divisors of k and k+1 which have the same number and sum of divisors.

4, 8, 8, 8, 8, 8, 16, 16, 16, 8, 16, 16, 16, 16, 16, 16, 16, 16, 32, 16, 16, 16, 16, 32, 16, 16, 16, 24, 16, 16, 16, 32, 32, 32, 16, 16, 32, 16, 32, 16, 16, 32, 32, 16, 32, 16, 16, 16, 16, 16, 32, 32, 16, 32, 16, 16, 64, 32, 16, 32, 16, 32, 16, 64, 32, 32, 16, 32, 32, 32, 32

Offset: 1

Author

Asher Auel, Jan 12 2000

Keywords

• nonn

Examples

			See example in A054004.
		

Links

• Amiram Eldar, Table of n, a(n) for n = 1..1831 (calculated using the b-file at A054004)

Crossrefs

Cf. A000005, A000203, A002961, A005237, A053249, A054004, A054005, A054007.

Programs

Mathematica

Select[Partition[Array[DivisorSigma[{0, 1}, #] &, 10^6], 2, 1], SameQ @@ # &][[All, 1, 1]] (* Michael De Vlieger, Nov 21 2019 *)

Formula

a(n) = tau(A054004(n)).

Extensions

More terms from Jud McCranie, Oct 15 2000