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A228491
Numbers k for which sum(first k primes) = 3*prime(m) for some m.
1
10, 16, 18, 28, 32, 34, 36, 44, 46, 54, 82, 136, 138, 246, 250, 276, 286, 362, 370, 378, 390, 554, 570, 586, 588, 668, 678, 684, 688, 690, 726, 766, 770, 826, 856, 860, 878, 880, 888, 924, 928, 932, 956, 962, 1048, 1160, 1174, 1210, 1264, 1286, 1292, 1506
OFFSET
1,1
EXAMPLE
a(1) = 10 because 2 + 3 + 5 + ... + 29 = 3*prime(14) and p(10) = 29 is the least such prime summand.
MATHEMATICA
z = 2800; f[n_] := Sum[Prime[k], {k, 1, n}]; p[n_] := If[PrimeQ[f[n]/3], 1, 0]; t = Table[p[n], {n, 1, z}]; Flatten[Position[t, 1]]
CROSSREFS
Sequence in context: A192221 A106695 A053747 * A295667 A241763 A233579
KEYWORD
nonn
AUTHOR
Clark Kimberling, Oct 01 2013
STATUS
approved