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%I #46 Sep 08 2022 08:46:21
%S 1,2,4,8,11,13,17,22,26,31,44,53,62,71,79,88,97,101,103,107,121,143,
%T 169,187,202,206,211,233,242,251,277,286,341,349,367,404,422,431,439,
%U 457,466,484,503,521,547,583,619,673,682,691,701,709,727,781,808,844
%N Numbers for which the sum of the digits of any divisor is a power of 2.
%C The prime numbers in A068807 belong to the sequence.
%e Divisors(8) = {1, 2, 4, 8} with sums of digits respectively 1, 2, 4, 8, powers of 2.
%e Divisors(13) = {1, 13} with sums of digits 1 and 4, powers of 2 .
%e Divisors(286) = {1, 2, 11, 13, 22, 26, 143, 286} with sums of digits respectively 1, 2, 2, 4, 4, 8, 16, powers of 2.
%o (Magma) sol:=[]; m:=1;for n in [1..850] do nr:=#[d: d in Divisors(n) | PrimeDivisors(&+Intseq(d)) eq [2]]; if nr eq #Divisors(n)-1 then sol[m]:=n; m:=m+1; end if; end for; sol;
%o (PARI) ispp(n) = (n==1) || (isprimepower(n, &p) && (p==2));
%o isok(n) = fordiv(n, d, if (!ispp(sumdigits(d)), return (0))); return (1); \\ _Michel Marcus_, Jun 12 2019
%Y Cf. A000005, A000079, A007953, A068807, A028838.
%K nonn,base
%O 1,2
%A _Marius A. Burtea_, Jun 11 2019
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