A126888 a(n) is the smallest positive integer such that floor(a(n)/d(a(n))) = n, or -1 if no such number exists, where d(m) is the number of positive divisors of m.

1, 5, 7, 28, 11, 13, 44, 17, 19, 63, 23, 51, 55, 29, 31, 49, 69, 37, 77, 41, 43, 91, 47, 147, 153, 53, 111, 115, 59, 61, 125, 129, 67, 207, 71, 73, 296, 155, 79, 121, 83, 680, 261, 89, 183, 185, 284, 97, 399, 101, 103, 209, 107, 109, 221, 113, 459, 235, 237, 363, 247, 249

Offset

1,2

Links

Hugo van der Sanden and D. W. Wilson, Table of n, a(n) for n = 1..10000

Mathematica

f[n_] := Block[{k = 1}, While[Floor[k/Length[Divisors[k]]] != n, k++ ]; k]; Table[f[n], {n, 62}] (* Ray Chandler, Jan 04 2007 *)

Crossrefs

Cf. A000005, A126889, A078709, A125056, A125057.

Sequence in context: A144392 A268701 A317166 * A358582 A185302 A179305

Adjacent sequences: A126885 A126886 A126887 * A126889 A126890 A126891

Keyword

nonn

Author

Leroy Quet, Dec 30 2006

Extensions

Extended by Ray Chandler, Jan 04 2007.

Added escape clause to definition at the suggestion of Hugo van der Sanden. - N. J. A. Sloane, Jul 01 2022

Status

approved