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 A363790 #6 Jun 24 2023 13:22:50 %S A363790 115,155,204,284,355,395,404,555,564,595,675,804,835,846,1075,1124, %T A363790 1164,1182,1266,1315,1434,1555,1604,1686,1795,1938,2075,2124,2195, %U A363790 2244,2315,2324,2358,2435,2595,3084,3204,3282,3366,4124,4195,4206,4235,4244,4364,4458 %N A363790 Numbers k such that k and k+1 are both primitive binary Niven numbers (A363787). %H A363790 Amiram Eldar, <a href="/A363790/b363790.txt">Table of n, a(n) for n = 1..10000</a> %e A363790 115 is a term since 115 and 116 are both primitive binary Niven numbers. %t A363790 binNivQ[n_] := Divisible[n, DigitCount[n, 2, 1]]; q[n_] := binNivQ[n] && ! (EvenQ[n] && binNivQ[n/2]); Select[Range[5000], q[#] && q[# + 1] &] %o A363790 (PARI) isbinniv(n) = !(n % hammingweight(n)); %o A363790 isprim(n) = isbinniv(n) && !(!(n%2) && isbinniv(n/2)); %o A363790 is(n) = isprim(n) && isprim(n+1); %Y A363790 Subsequence of A049445, A330931 and A363787. %Y A363790 Subsequences: A363791, A363792. %K A363790 nonn,base %O A363790 1,1 %A A363790 _Amiram Eldar_, Jun 22 2023