A032549 Numbers that, when expressed in base 7 and then interpreted in base 10, yield a multiple of the original number.

1, 2, 3, 4, 5, 6, 51, 102, 105, 153, 156, 207, 210, 258, 261, 312, 315, 2589, 2590, 2601, 2753, 5354, 5355, 5506, 8108, 8259, 8260, 10861, 11013, 11025, 13614, 13615, 13626, 13766, 13778, 16379, 16380, 16531, 33045, 140403, 289065, 1123224

Offset: 1

Author

Patrick De Geest, Apr 15 1998

Keywords

• nonn
• base

Comments

Decimal 'base-7 looking' numbers divided by their actual base-7 values (n) is an integer.

Links

• Giovanni Resta, Table of n, a(n) for n = 1..70 (terms < 10^12, first 63 terms from Paolo P. Lava)

Crossrefs

Cf. A032548, A032550. See also A032532 for explanation.

Programs

Mathematica

Select[Range@ 300000, Mod[ FromDigits[ IntegerDigits[#, 7]], #] == 0 &] (* Giovanni Resta, Oct 21 2019 *)

Extensions

Offset set to 1 by Giovanni Resta, Oct 21 2019

Name edited by Jon E. Schoenfield, Oct 25 2019