

A024684


Number of ways prime(n) is a sum of three distinct primes.


4



0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 6, 9, 11, 13, 13, 15, 18, 17, 19, 25, 26, 28, 32, 31, 37, 32, 39, 44, 51, 54, 48, 60, 55, 62, 64, 73, 80, 79, 74, 89, 84, 92, 86, 92, 107, 119, 105, 118, 122, 117, 135, 143, 146, 147, 141, 149, 159, 157, 176, 175, 190, 180
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OFFSET

1,9


LINKS

Zak Seidov and T. D. Noe, Table of n, a(n) for n = 1..10000 (first 2000 terms from Zak Seidov)
Wikipedia, Goldbach's weak conjecture


FORMULA

a(n) = A125688(prime(n)).  R. J. Mathar, Jun 09 2014


EXAMPLE

a(9) = 2 because prime(9) = 23 and 23 = 3 + 7 + 13 = 5 + 7 + 11.


MATHEMATICA

last = 313; pp = PrimePi[last]; t = Select[Sort[Tally[Select[Total /@ Subsets[Prime[Range[2, pp]], {3}], PrimeQ]]], #[[1]] <= last &]; Join[{0, 0, 0, 0, 0, 0, 0}, Transpose[t][[2]]] (* T. D. Noe, Apr 15 2013 *)


CROSSREFS

Cf. A002372, A002375, A224534.
Sequence in context: A122168 A017856 A087412 * A265538 A037850 A037886
Adjacent sequences: A024681 A024682 A024683 * A024685 A024686 A024687


KEYWORD

nonn


AUTHOR

Clark Kimberling


STATUS

approved



