A057922 d(n) divides d(n+1), where d(n) is number of positive divisors of n.

1, 2, 5, 7, 11, 13, 14, 17, 19, 21, 23, 26, 29, 31, 33, 34, 37, 38, 39, 41, 43, 44, 47, 49, 53, 55, 57, 59, 61, 65, 67, 69, 71, 73, 75, 77, 79, 83, 85, 86, 87, 89, 93, 94, 95, 97, 98, 101, 103, 104, 107, 109, 113, 116, 118, 119, 122, 125, 127, 129, 131, 133, 134, 135

Offset: 0

Author

Leroy Quet, Nov 11 2000

Keywords

• nonn

Examples

			11 is included because d(11) = 2 divides d(12) = 6.
		

Links

• Ivan Neretin, Table of n, a(n) for n = 0..10000

Crossrefs

Cf. A057921, A005237.

Programs

Mathematica

Select[Range@150, Divisible @@ DivisorSigma[0, {# + 1, #}] &] (* Ivan Neretin, May 29 2015 *)
Position[Partition[DivisorSigma[0,Range[150]],2,1],?(Divisible[#[[2]], #[[1]]]&),1,Heads->False]//Flatten (* _Harvey P. Dale, May 08 2019 *)