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A126204
Least prime representable as the arithmetic mean of two other primes in n different ways.
6
2, 5, 11, 17, 37, 53, 89, 71, 101, 179, 137, 193, 233, 257, 251, 401, 311, 373, 347, 457, 661, 479, 547, 599, 617, 641, 683, 907, 881, 773, 827, 809, 941, 1033, 977, 1289, 1201, 1187, 1229, 1223, 1277, 1361, 1597, 1493, 1447, 1499, 1451, 1549, 1487, 1709, 1933
OFFSET
0,1
COMMENTS
a(n)=A000040(A137700(n)); A071681(A137700(n))=n and A071681(m)<>n for m < A137700(n). - Reinhard Zumkeller, Feb 07 2008
LINKS
MATHEMATICA
f[n_] := Block[{c = 0, k = PrimePi@n - 1}, While[k > 0, If[ PrimeQ[2n - Prime@k], c++ ]; k-- ]; c]; t = Table[0, {1000}]; Do[ p = Prime@n; a = f@p; If[a < 1001 && t[[a]] == 0, t[[a]] = p; Print[{a, p}]], {n, 8900}]
CROSSREFS
Cf. A071681.
Sequence in context: A027426 A133928 A372197 * A091936 A153145 A174003
KEYWORD
nonn
AUTHOR
Robert G. Wilson v, Mar 22 2007
EXTENSIONS
Start of b-file modified to match sequence by N. J. A. Sloane, Aug 31 2009
STATUS
approved