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%I #16 Mar 17 2024 03:16:10
%S 7,61,73,547,4921,703,5905,44287,6481,398581,478297,3587227,512461,
%T 58807,32285041,38742049,530713,290565367,42521761,2615088301,
%U 373584043,4780783,3138105961,23535794707,43040161,211822152361,3472494301
%N Numbers of the form (3^s+1)/(3^r+1) for s > 1, 1 <= r <= s-1.
%C (b^s+1) / (b^r+1) is an integer iff s/r is odd. - Jose Brox (tautocrona(AT)terra.es), Dec 27 2005
%o (PARI) for(x=2,26, for(y=1,x-1,if(Mod(2^x+1,2^y+1),0,print1((3^x+1)/(3^y+1)",")))) \\ The Mod(2^x+1,2^y+1) is not a bug, since the exponents do not depend on the base in which they are calculated.
%Y Cf. A079665, A079581, A079673.
%K nonn
%O 1,1
%A Jose R. Brox (tautocrona(AT)terra.es), Jan 25 2003
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