A119496 Numbers n such that 2^n, 3^n, 5^n and 7^n have even digit sum.

15, 64, 83, 90, 106, 107, 120, 122, 135, 168, 173, 180, 181, 185, 193, 198, 222, 229, 239, 242, 289, 299, 347, 356, 364, 369, 407, 424, 447, 458, 462, 470, 479, 481, 503, 542, 552, 568, 580, 583, 607, 612, 648, 657, 676, 683, 684, 688, 742, 758, 787

Offset

1,1

Links

Table of n, a(n) for n=1..51.

Example

{2^15,3^15,5^15,7^15}={32768,14348907,30517578125,4747561509943} with even digit sum {26,36,44,64}.

Mathematica

Select[Range[800], AllTrue[Total/@(IntegerDigits/@({2, 3, 5, 7}^#)), EvenQ]&] (* Harvey P. Dale, Oct 13 2022 *)

Prog

(PARI) isok(n) = !(sumdigits(2^n) % 2) && !(sumdigits(3^n) % 2) && !(sumdigits(5^n) % 2) && !(sumdigits(7^n) % 2); \\ Michel Marcus, Oct 10 2013

Crossrefs

Subsequence of A118734 and of A118867.

Sequence in context: A135972 A138104 A152099 * A044153 A044534 A063483

Adjacent sequences: A119493 A119494 A119495 * A119497 A119498 A119499

Keyword

base,nonn

Author

Zak Seidov, May 26 2006

Status

approved