A024680 Number of ways prime(n) is a sum of 3 odd nonprimes r,s,t satisfying 1 <= r < s < t.

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 1, 2, 1, 1, 3, 7, 6, 5, 9, 10, 7, 9, 17, 15, 19, 15, 24, 19, 34, 29, 31, 42, 42, 55, 58, 60, 57, 60, 71, 88, 85, 97, 92, 106, 129, 137, 132, 152, 142, 153, 176, 175, 182, 196, 212, 231, 239, 238, 250, 256, 306, 305, 326, 314, 382, 394, 394, 433, 413, 437

Offset

1,12

Links

Robert Israel, Table of n, a(n) for n = 1..1000

Maple

N:= 1000: # to get terms for primes <= N
P, NP:= selectremove(isprime, [seq(i, i=1..N, 2)]):
V:= Vector(N):
for ri from 1 while NP[ri] <= N/3 do
  for si from ri+1 while NP[ri]+2*NP[si] <= N do
    for ti from si+1  do
        x:= NP[ri]+NP[si]+NP[ti];
        if x > N then break fi;
        V[x]:= V[x]+1;
od od od:
0, seq(V[P[i]], i=1..nops(P)); # Robert Israel, Nov 03 2019

Crossrefs

Sequence in context: A266506 A134303 A078997 * A083531 A003417 A358549

Adjacent sequences: A024677 A024678 A024679 * A024681 A024682 A024683

Keyword

nonn

Author

Clark Kimberling

Status

approved