This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A175169 #32 Sep 05 2025 10:24:04 %S A175169 1,2,5,70 %N A175169 Numbers k that divide the sum of digits of 2^k. %C A175169 No other terms <= 200000. - _Harvey P. Dale_, Dec 16 2010 %C A175169 No other terms <= 1320000. - _Robert G. Wilson v_, Dec 18 2010 %C A175169 There are almost certainly no further terms. %t A175169 Select[Range[1000],Divisible[Total[IntegerDigits[2^#]],#]&] (* _Harvey P. Dale_, Dec 16 2010 *) %o A175169 (PARI) is(n)=sumdigits(2^n)%n==0 \\ _Charles R Greathouse IV_, Sep 06 2016 %Y A175169 Sum of digits of k^n mod n: (k=2) A000079, A001370, A175434, A175169; (k=3) A000244, A004166, A175435, A067862; (k=5) A000351, A066001, A175456; (k=6) A000400, A066002, A175457, A067864; (k=7) A000420, A066003, A175512, A067863; (k=8) A062933; (k=13) A001022, A175527, A175528, A175525; (k=21) A175589; (k=167) A175558, A175559, A175560, A175552. %K A175169 nonn,base,changed %O A175169 1,2 %A A175169 _N. J. A. Sloane_, Dec 03 2010