login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A135122 Numbers such that the digital sum base 2 and the digital sum base 3 and the digital sum base 4 all are equal. 3
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 (list; graph; refs; listen; history; text; internal format)
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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 20 02:46 EDT 2019. Contains 323412 sequences. (Running on oeis4.)