1,1

p^2 divides a(n) = (p + 1)^p - 1, p = Prime[n]. Quotients a(n)/Prime[n]^2 are listed in A137665(n) = {2,7,311,42799,6140565047,4696537119847,7563707819165039903,...}. Least prime factors of A137665(n) = a(n)/Prime[n]^2 are listed in A128456(n) = {2,7,311,127,23,157,7563707819165039903,...}. Largest prime factors A137665(n) = a(n)/Prime[n]^2 are listed in A137666(n) = {2,7,311,337,266981089,29914249171,7563707819165039903,...}.

a(n) = (Prime[n] + 1)^Prime[n] - 1.

Table[ (Prime[n] + 1)^Prime[n] - 1, {n, 1, 15} ]

Cf. A128452, A128456, A128356, A128357, A137665, A137666.

Sequence in context: A037205 A060071 A084096 this_sequence A014392 A008462 A043078

Adjacent sequences: A137661 A137662 A137663 this_sequence A137665 A137666 A137667

nonn

Alexander Adamchuk (alex(AT)kolmogorov.com), Feb 04 2008