

A087916


Number of ordered ways to write 2n+1 as a sum of 3 odd primes.


4



0, 0, 0, 0, 1, 3, 6, 7, 9, 12, 16, 18, 21, 27, 30, 30, 34, 36, 42, 46, 48, 48, 51, 63, 60, 64, 81, 75, 76, 87, 87, 90, 102, 105, 97, 117, 114, 105, 144, 129, 126, 159, 141, 145, 177, 162, 160, 195, 186, 153, 207, 201, 171, 237, 210, 187, 255, 234, 222, 279
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OFFSET

0,6


LINKS

T. D. Noe, Table of n, a(n) for n = 0..10000


MATHEMATICA

nn = 100; lim = 2*nn + 17; ps = Prime[Range[2, nn + 1]]; t = Table[0, {lim}]; Do[s = i + j + k; If[s <= lim, t[[s]]++], {i, ps}, {j, ps}, {k, ps}]; Take[t, {1, lim, 2}] (* T. D. Noe, Apr 10 2014 *)


PROG

(PARI) for(n=0, 100, t=2*n+1; c=0; for(k=2, t, for(l=2, t, for(m=2, t, tt=prime(k)+prime(l)+prime(m); if(tt>2*n+1, break); if(tt==2*n+1, c=c+1)))); print1(c", "))


CROSSREFS

Cf. A007963 (unordered), A068307 (with 2).
Cf. A087917.
Sequence in context: A061641 A085359 A231664 * A296693 A282585 A280210
Adjacent sequences: A087913 A087914 A087915 * A087917 A087918 A087919


KEYWORD

nonn,easy


AUTHOR

Ralf Stephan, Oct 18 2003


EXTENSIONS

Leading zeros added by T. D. Noe, Apr 10 2014


STATUS

approved



