A135122 Numbers such that the digital sum base 2 and the digital sum base 3 and the digital sum base 4 all are equal.

1, 21, 261, 273, 17748, 17749, 20820, 20821, 65620, 65621, 70740, 70741, 83268, 83269, 86292, 86293, 1066068, 1066069, 1070420, 1135701, 1135893, 1135953, 5326161, 5330001, 5330241, 5330260, 5330261, 5506389, 5525829, 5526801, 5571909, 5574933, 5592321

Offset

1,2

Links

Giovanni Resta, Table of n, a(n) for n = 1..10000

Example

a(2)=21, since ds_2(21)=ds_3(21)=ds_10(21)=3, where ds_x=digital sum base x.

Mathematica

Select[Range[5600000], Length[Union[Table[Total[IntegerDigits[#, n]], {n, 2, 4}]]]==1&] (* Harvey P. Dale, Aug 14 2013 *)

Prog

(PARI) isok(n) = my(sd2=sumdigits(n, 2)); (sd2==sumdigits(n, 3)) && (sd2==sumdigits(n, 4)); \\ Michel Marcus, Aug 08 2018

Crossrefs

Cf. A007953, A054899, A131451, A133620, A133900, A134599, A135100, A135110, A135120, A037308.

Sequence in context: A241632 A323972 A125433 * A231380 A045505 A169895

Adjacent sequences: A135119 A135120 A135121 * A135123 A135124 A135125

Keyword

nonn,base

Author

Hieronymus Fischer, Dec 31 2007

Extensions

a(31)-a(33) from Giovanni Resta, Aug 06 2018

Status

approved