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 A141467 #15 Feb 21 2021 03:46:06 %S A141467 1,6,10,12,8,12,10,16,20,18,16,20,14,24,32,16,36,20,24,40,28,20,40,36, %T A141467 22,32,32,30,28,48,26,48,60,40,40,32,54,56,40,44,32,48,34,60,80,64,42, %U A141467 40,52,50,72,40,80,44,84,48,64,108,44,60,80,46,64,56,72,96,52,68,50,88,96,70,84 %N A141467 a(1)=1; for n > 1, a(n) is the product of prime factors of the n-th composite, but with the largest prime incremented by 3 and the smallest decremented by 1. %C A141467 In the prime number decomposition of k=A002808(n), one instance of the largest prime, pmax=A052369(n), is replaced by pmax+3 and one instance of the smallest prime, pmin=A056608(n), is replaced by pmin-1. a(n) is the product of this modified set of factors if nonprime. The case of n=1, k=4, is the only case where this modified product (2+3)*(2-1)=5 is prime and listed as a(1)=1. %F A141467 a(n) = k*(pmax+3)*(pmin-1)/(pmin*pmax), n > 1, where k=A002808(n), pmin=A056608(n), pmax=A052369(n). %e A141467 n-th composite %e A141467 n & factorization transformed product %e A141467 - --------------- -------------------------- %e A141467 1 4 = 2*2 (2-1)*(2+3) = 1*5 = 5 (prime) %e A141467 2 6 = 2*3 (2-1)*(3+3) = 1*6 = 6 = a(2) %e A141467 3 8 = 2*2*2 (2-1)*2*(2+3) = 1*2*5 = 10 = a(3) %e A141467 4 9 = 3*3 (3-1)*(3+3) = 2*6 = 12 = a(4) %e A141467 5 10 = 2*5 (2-1)*(5+3) = 1*8 = 8 = a(5) %e A141467 6 12 = 2*2*3 (2-1)*2*(3+3) = 1*2*6 = 12 = a(6) %e A141467 7 14 = 2*7 (2-1)*(7+3) = 1*10 = 10 = a(7) %K A141467 nonn %O A141467 1,2 %A A141467 _Juri-Stepan Gerasimov_, Aug 08 2008 %E A141467 Edited by _R. J. Mathar_, Aug 14 2008 %E A141467 Further edits by _Jon E. Schoenfield_, Feb 20 2021