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%I #22 Feb 10 2021 13:53:30
%S 1,5,15,25,55,91,137,525,625,925,3967,5995,7625,10767,25087,57225,
%T 68817,565027,591415,2515825,2757625,4162019,5276309,96689255,
%U 115686005,133890625,242899421,492029715,588620625,1839399055,7786281065,11231388063,17251448809,71050380625
%N Numbers k such that A007088(k) == 1 (mod k).
%C All terms are odd.
%e a(3) = 15 is a term because 15 = 1111_2 and 1111 == 1 (mod 15).
%p filter:= t -> convert(t,binary) mod t = 1: filter(1):= true:
%p select(filter, [seq(i,i=1..10^7,2)]);
%t Block[{a = {1}, k}, Do[If[Mod[FromDigits@ IntegerDigits[i, 2], i] == 1, AppendTo[a, i]], {i, 2, 10^7}]; a] (* _Michael De Vlieger_, Dec 12 2020 *)
%o (PARI) isok(n) = Mod(fromdigits(binary(n)), n) == 1;
%o forstep(k=1, 10^7, 2, if(isok(k), print1(k, ", "))); \\ _Daniel Suteu_, Dec 12 2020
%Y Cf. A007088, A339566.
%K nonn,base
%O 1,2
%A _Robert Israel_, Dec 09 2020
%E a(30)-a(34) from _Daniel Suteu_, Dec 12 2020