cp's OEIS Frontend

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.

A141554 Transformed nonprime products of prime factors of the composites, the largest prime decremented by 2 and the smallest prime incremented by 2.

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%I A141554 #4 Mar 30 2012 18:52:27
%S A141554 0,4,0,12,8,20,15,0,12,24,25,36,16,21,44,15,40,36,0,45,60,35,24,68,55,
%T A141554 48,60,72,45,84,32,45,60,75,88,36,63,80,85,108,72,116,75,0,77,108,120,
%U A141554 105,100,48,140,75,136,81,132,96,45,156,120,105,164,135,144,108,99,168
%N A141554 Transformed nonprime products of prime factors of the composites, the largest prime decremented by 2 and the smallest prime incremented by 2.
%C A141554 In the prime number decomposition of k=A002808(i), i=1,2,3,.., one instance of the largest prime, pmax=A052369(i), is replaced by pmax-2 and one instance of the smallest prime, pmin=A056608(i), is replaced by pmin+2. If the product of this modified list of factors, k*(pmax-2)*(pmin+2)/(pmin*pmax), is nonprime, it is added to the sequence.
%e A141554 k(1)=4=(p(max)=2)*(p(min)=2), transformed (2-2)*(2+2)=0*4=0=a(1).
%e A141554 k(2)=6=(p(max)=3)*(p(min)=2), transformed (3-2)*(2+2)=1*4=4=a(2).
%e A141554 k(3)=8=(p(max)=2)*(p=2)*(p(min)=2), transformed (2-2)*2*(2+2)=0*2*4=0=a(3).
%e A141554 k(4)=9=(p(max)=3)*(p(min)=3), transformed (3-2)*(3+2)=1*5=5 (prime, skipped).
%e A141554 k(5)=10=(p(max)=5)*(p(min)=2), transformed (5-2)*(2+2)=3*4=12=a(4).
%Y A141554 Cf. A141218, A141219, A141220, A141284.
%K A141554 nonn
%O A141554 1,2
%A A141554 _Juri-Stepan Gerasimov_, Aug 14 2008
%E A141554 Edited and corrected by _R. J. Mathar_, Aug 18 2008