login
A074311
a(1) = 1; a(2) = 2; a(n) = smallest number greater than the previous term such that the average of three successive terms is a prime.
2
1, 2, 3, 4, 8, 9, 16, 26, 27, 34, 50, 57, 70, 74, 75, 88, 104, 111, 112, 116, 153, 178, 188, 207, 238, 242, 243, 268, 278, 285, 286, 308, 327, 358, 362, 381, 394, 416, 417, 424, 452, 453, 466, 470, 501, 502, 506, 519, 538, 566, 567, 574, 590, 597, 610, 614, 615
OFFSET
1,2
COMMENTS
Inspired by A073627, A073628. Primes generated in the sequence are in A075551. Primes generated in A073628 are in A075552.
LINKS
EXAMPLE
a(5) = 8 because 1/3(a(3) + a(4) + a(5)) is a prime.
MATHEMATICA
sngpt[{a_, b_}]:=Module[{k=b+1}, While[CompositeQ[Mean[{a, b, k}]], k++]; {b, k}]; NestList[sngpt, {1, 2}, 60][[All, 1]] (* Harvey P. Dale, May 29 2019 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Zak Seidov, Sep 23 2002
STATUS
approved