A100460 Smallest prime which is equal to the sum of three distinct primes in exactly n ways, or 0 if no such prime exists.

19, 23, 29, 31, 37, 41, 0, 0, 47, 0, 53, 0, 59, 0, 67, 0, 73, 71, 79, 0, 0, 0, 0, 0, 83, 89, 0, 97, 0, 0, 103, 101, 0, 0, 0, 0, 107, 0, 113, 0, 0, 0, 0, 127, 0, 0, 0, 139, 0, 0, 131, 0, 0, 137, 151, 0, 0, 0, 0, 149, 0, 157, 0, 163, 0, 0, 0, 0, 0, 0, 0, 0, 167, 181, 0, 0, 0, 0, 179, 173, 0

Offset

1,1

Links

Table of n, a(n) for n=1..81.

Example

a(1)=19 since 19=3+5+11; a(2)=23 since 23=5+7+11=3+7+13.
a(5)=37 since 37=3+5+29=3+11+23=5+13+19=7+11+19=7+13+17.

Mathematica

nn=100; t=Table[0, {nn}]; s=Table[{}, {nn}]; Do[p=Prime[i]+Prime[j]+Prime[k]; If[PrimeQ[p], pin=PrimePi[p]; If[pin<=nn, t[[pin]]++; AppendTo[s[[pin]], {i, j, k}]]], {i, nn}, {j, i+1, nn}, {k, j+1, nn}]; Table[pos=Position[t, n]; If[pos=={}, 0, Prime[pos[[1, 1]]]], {n, nn}]

Crossrefs

Sequence in context: A226687 A070299 A159021 * A166061 A224534 A073319

Adjacent sequences: A100457 A100458 A100459 * A100461 A100462 A100463

Keyword

nonn

Author

Giovanni Teofilatto, Nov 23 2004

Extensions

Corrected and extended by T. D. Noe, Nov 23 2004

Status

approved