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
KEYWORD
nonn,base
AUTHOR
Hieronymus Fischer, Dec 31 2007
EXTENSIONS
a(31)-a(33) from Giovanni Resta, Aug 06 2018
STATUS
approved