1,1

a(1)=7849 because 5^6-6^5=7849=47*167 is a semiprime.

Cf. A007925 n^(n+1)-(n+1)^n, A072179 n^(n+1)-(n+1)^n is prime, A099499 primes of the form n^(n+1)-(n+1)^n, A099497 n^(n+1)-(n+1)^n is a semiprime.

Adjacent sequences: A099495 A099496 A099497 this_sequence A099499 A099500 A099501

Sequence in context: A017597 A043520 A045277 this_sequence A045292 A115426 A155178

nonn

Hugo Pfoertner (hugo(AT)pfoertner.org), Oct 19 2004