A064162 Least abundant number divisible by n.

12, 12, 12, 12, 20, 12, 42, 24, 18, 20, 66, 12, 78, 42, 30, 48, 102, 18, 114, 20, 42, 66, 138, 24, 100, 78, 54, 56, 174, 30, 186, 96, 66, 102, 70, 36, 222, 114, 78, 40, 246, 42, 258, 88, 90, 138, 282, 48, 196, 100, 102, 104, 318, 54, 220, 56, 114, 174, 354, 60, 366

Offset

1,1

Links

Harry J. Smith, Table of n, a(n) for n=1..1000

Example

The first eight abundant numbers are 12, 18, 20, 24, 30, 36, 40 and 42. But only the last one is divisible by 7. Therefore a(7) = 42.

Mathematica

Do[ k = 11; While[ m = DivisorSigma[ 1, k ] - 2k; m <= 0 || Mod[ k, n ] != 0, k++ ]; Print[ k ], {n, 1, 75} ]
With[{abnos=Select[Range[500], DivisorSigma[1, #]>2#&]}, Table[ SelectFirst[ abnos, Divisible[ #, n]&], {n, 70}]] (* The program uses the SelectFirst function from Mathematica version 10 *) (* Harvey P. Dale, Nov 29 2015 *)

Prog

(PARI) { for (n=1, 1000, k=11; until (sigma(k) - k > k && k%n == 0, k++); write("b064162.txt", n, " ", k) ) } \\ Harry J. Smith, Sep 09 2009

Crossrefs

Sequence in context: A123896 A122878 A302341 * A028996 A113595 A109053

Adjacent sequences: A064159 A064160 A064161 * A064163 A064164 A064165

Keyword

easy,nonn

Author

Robert G. Wilson v, Sep 15 2001

Status

approved