1,2

Table of n, a(n) for n=1..67.

1st nonprime = 1 (has no prime factors); a(1) = empty product = 1.

2nd nonprime = 4 = (p(max)=2)*(p(min)=2); a(2) = (2+1)*(2-1) = 3*1 = 3.

3rd nonprime = 6 = (p(max)=3)*(p(min)=2); a(3) = (3+1)*(2-1) = 4*1 = 4.

4th nonprime = 8 = (p(max)=2)*(p=2)*(p(min)=2); a(4) = (2+1)*2*(2-1) = 3*2*1 = 6.

Sequence in context: A168170 A225794 A206769 * A069211 A242822 A240675

Adjacent sequences: A141216 A141217 A141218 * A141220 A141221 A141222

nonn

Juri-Stepan Gerasimov, Aug 07 2008

Three terms corrected by R. J. Mathar, Aug 18 2008

Entry revised by Jon E. Schoenfield, Mar 09 2014, following revision of A141218 by N. J. A. Sloane

approved