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 A177768 #19 Sep 06 2021 16:07:55
%S A177768 7,15,23,31,39,63,79,95,127,175,207,255,511,543,607,767,1023,1279,
%T A177768 2047,4095,4423,5135
%N A177768 Positions of decreases in sequence A061712 (related to Hamming weights of primes).
%C A177768 Is the sequence infinite?
%C A177768 All terms listed are of the form == 7 (mod 8). Is there a reason for this phenomenon?
%C A177768 Conjecture: The numbers 2^k-1 for k > 2 are terms. - _Chai Wah Wu_, Sep 02 2021
%F A177768 {n : A061712(n) < A061712(n-1)}.
%Y A177768 Cf. A061712.
%K A177768 nonn,more,base
%O A177768 1,1
%A A177768 _Vladimir Shevelev_, May 13 2010
%E A177768 a(20)-a(22) from _Chai Wah Wu_, Sep 06 2021