A053789 a(n) = A020639(A053790(n)).

2, 2, 2, 7, 2, 3, 2, 2, 2, 3, 2, 3, 2, 3, 2, 7, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 41, 2, 3, 2, 3, 2, 3, 2, 3, 2, 59, 2, 7, 2, 3, 2, 3, 2, 7, 2, 37, 2, 2, 5, 2, 2, 89, 2, 3, 2, 3, 2, 7, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 13, 2, 109, 2, 2, 17, 2, 2, 2, 7, 2, 7, 2, 2, 7, 2

Offset

1,1

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Example

a(4) = 7 because the sum of the first 8 primes is 77 and 7 is its least prime divisor.

Maple

N:= 2000: # to use primes <= N
P:= select(isprime, [2, seq(i, i=3..N, 2)]):
A053790:= remove(isprime, ListTools:-PartialSums(P)):
map(t -> min(numtheory:-factorset(t)), A053790); # Robert Israel, Jan 29 2018

Crossrefs

Cf. A013918, A053790, A020639.

Sequence in context: A129365 A125838 A021453 * A115596 A202033 A340742

Adjacent sequences: A053786 A053787 A053788 * A053790 A053791 A053792

Keyword

easy,nonn

Author

Enoch Haga, Mar 27 2000

Extensions

Edited by N. J. A. Sloane, Mar 16 2008, following explication by R. J. Mathar, Feb 26 2008

Status

approved