A141552 Transformed products of prime factors of the composites, the largest prime and smallest prime incremented by 1.

9, 12, 18, 16, 18, 24, 24, 24, 36, 36, 36, 32, 36, 48, 36, 42, 48, 48, 54, 72, 48, 54, 48, 72, 60, 56, 72, 72, 72, 72, 72, 96, 64, 90, 72, 84, 108, 72, 96, 80, 90, 108, 96, 96, 144, 84, 108, 108, 96, 120, 144, 114, 120, 120, 96, 126, 144, 144, 126, 144, 108, 132, 120, 144

Offset

1,1

Comments

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+1 and one instance of the smallest prime, pmin=A056608(i), is replaced by pmin+1. The product of this modified list of factors, k*(pmax+1)*(pmin+1)/(pmin*pmax), is added to the sequence.

Links

Table of n, a(n) for n=1..64.

Example

k(1)=4=(p(max)=2)*(p(min)=2), transformed (2+1)*(2+1)=3*3=9=a(1).
k(2)=6=(p(max)=3)*(p(min)=2), transformed (3+1)*(2+1)=4*3=12=a(2).
k(6)=12=(p(max)=3)*(p=2)*(p(min)=2), transformed (3+1)*2*(2+1)=4*2*3=24=a(6), etc.

Crossrefs

Cf. A141218, A141219, A141220, A141284.

Sequence in context: A199593 A356842 A174525 * A375241 A317720 A162822

Adjacent sequences: A141549 A141550 A141551 * A141553 A141554 A141555

Keyword

nonn

Author

Juri-Stepan Gerasimov, Aug 14 2008

Extensions

Edited and corrected by R. J. Mathar, Aug 18 2008

Status

approved