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 A372134 #7 May 12 2024 11:18:08 %S A372134 -1,1,2,3,4,5,8,7,6,10,16,9,32,20,40,11,64,18,128,36,80,160,256,17,12, %T A372134 320,14,72,512,13,1024,19,640,1280,2560,15,2048,5120,10240,34,4096,26, %U A372134 8192,144,288,20480,16384,25,24,576,40960,1152,32768,68,81920,136 %N A372134 Prime shadows (A181819) linearly transformed to generate odd numbers, multiplied by 2^(A064839 - 1). %C A372134 a(n>1) contains all positive integers exactly once. %F A372134 a(n) = (2 * A181819(n) - 3) * 2^(k - 1), where k is the number of occurrences of the same prime signature of n in (1..n) (A064839). %t A372134 z = 100; prisigs = Table[If[n == 1, {}, Sort[Last /@ FactorInteger[n]]], {n, z}]; %t A372134 exps = Table[Count[Take[prisigs, n], prisigs[[n]]], {n, z}];(* A064839 *) %t A372134 Table[2^(exps[[n]] - 1) (2 Times @@ Prime[prisigs[[n]]] - 3), {n, z}] %Y A372134 Cf. A064839, A181819, A372133. %K A372134 sign %O A372134 1,3 %A A372134 _Friedjof Tellkamp_, Apr 20 2024