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 A141466 #14 Feb 21 2021 03:32:57 %S A141466 1,4,4,4,6,8,4,6,8,12,10,8,16,12,12,12,12,8,20,16,24,12,18,24,16,18, %T A141466 20,24,22,16,36,20,32,24,18,40,24,36,28,24,30,36,16,48,30,32,44,30,24, %U A141466 36,40,36,60,36,32,36,40,36,64,42,56,40,36,72,44,60,46,72,32,42,60,40,48,48,60,52 %N A141466 Nonprime transformed products of prime factors of the composites, the largest and smallest prime decremented by 1. %C A141466 In the prime factorization of k=A002808(i), i=1,2,3,..., one instance of the largest prime, pmax=A052369(i), is replaced by pmax-1 and one instance of the smallest prime, pmin=A056608(i), is replaced by pmin-1. If the product of this modified set of factors, k*(pmax-1)*(pmin-1)/(pmin*pmax), is nonprime, it is appended to the sequence. %e A141466 composite k transformed product %e A141466 ----------- ------------------------- %e A141466 4 = 2*2 (2-1)*(2-1) = 1*1 = 1 = a(1) %e A141466 6 = 2*3 (2-1)*(3-1) = 1*2 = 2 (prime) %e A141466 8 = 2*2*2 (2-1)*2*(2-1) = 1*2*1 = 2 (prime) %e A141466 9 = 3*3 (3-1)*(3-1) = 2*2 = 4 = a(2) %e A141466 10 = 2*5 (2-1)*(5-1) = 1*4 = 4 = a(3) %e A141466 12 = 2*2*3 (2-1)*2*(3-1) = 1*2*2 = 4 = a(4) %e A141466 14 = 2*7 (2-1)*(7-1) = 1*6 = 6 = a(5) %K A141466 nonn %O A141466 1,2 %A A141466 _Juri-Stepan Gerasimov_, Aug 08 2008 %E A141466 Definition rephrased by _R. J. Mathar_, Aug 14 2008 %E A141466 Edited by _Jon E. Schoenfield_, Feb 20 2021