1,1

Note that this is not what is meant by "prime endofunction" in A048888.

n such that A001372(n) is in A000040. n such that A124933(n) = 1, where A124933(n) = number of prime divisors (counted with multiplicity) of number of endofunctions on n points (A001372).

a(1) = 2 because number of endofunctions on 2 points A001372(2) = 3 is prime.

a(2) = 3 because A001372(3) = 7 is prime.

a(3) = 4 because A001372(4) = 19 is prime.

a(4) = 5 because A001372(5) = 47 is prime.

a(5) = 34 because A001372(34) = 767562358514099 is prime.

a(6) = 51 because A001372(51) = 62776430822871324190789 is prime.

Cf. A000040, A001372 = number of endofunctions on n points, A124933 = number of prime divisors (counted with multiplicity) of number of endofunctions on n points (A001372), A048888.

Sequence in context: A086130 A024636 A004845 this_sequence A037401 A062509 A061537

Adjacent sequences: A124125 A124126 A124127 this_sequence A124129 A124130 A124131

nonn,less

Jonathan Vos Post (jvospost3(AT)gmail.com), Nov 29 2006