In this sequence a(3) and a(5) are primes. Also a(1)+1, a(6)+1 and a(7)+1 are primes. And a(10)-1 is prime. These may at some future time begin three new sequences.
Table of n, a(n) for n=0..11.
Find the absolute value of second differences of overlapping pairs of values of n
a(0)=4432 because the first two values of first differences in A128193 are 140 and 4572. 4572-140=4432, the first second difference.
Cf. A005849 A128193.
Sequence in context: A108008 A275773 A060363 * A184091 A309487 A206016
Adjacent sequences: A128191 A128192 A128193 * A128195 A128196 A128197
Enoch Haga, Feb 18 2007