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A053789
a(n) = A020639(A053790(n)).
2
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
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
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