A118734 Numbers k such that 2^k and 3^k have even digit sum.

6, 15, 33, 37, 42, 43, 44, 46, 47, 50, 54, 55, 57, 58, 64, 67, 70, 71, 77, 82, 83, 84, 85, 90, 95, 102, 106, 107, 112, 116, 120, 122, 126, 129, 135, 136, 138, 140, 142, 149, 154, 161, 168, 170, 173, 176, 178, 179, 180, 181, 185, 193, 195, 198, 200, 207, 209, 210, 217

Offset: 1

Author

Zak Seidov, May 22 2006

Keywords

• nonn
• base

Links

• Robert Israel, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. Intersection of A118730 and A118733.

Programs

Maple

filter:= proc(n) convert(convert(2^n,base,10),`+`)::even and convert(convert(3^n,base,10),`+`)::even end proc:
select(filter, [$1..1000]); # Robert Israel, Apr 12 2021

Mathematica

Select[Range[220], And @@ ((Mod[ Plus @@ IntegerDigits[ # ], 2] == 0 &) /@ {2^#, 3^#}) &] (* Ray Chandler, Jun 10 2006 *)

Extensions

Extended by Ray Chandler, Jun 10 2006