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REFERENCES
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Fred Cohen and J. L. Selfridge, Not every number is the sum or difference of two prime powers, Math. Comput. 29 (1975), pp. 79-81.
P. Erdos, On integers of the form 2^k + p and some related problems, Summa Brasil. Math. 2 (1950), pp. 113-123.
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LINKS
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Table of n, a(n) for n=1..4.
Chris Caldwell, The Prime Glossary, Riesel number
Chris Caldwell, The Prime Glossary, Sierpinski number
M. Filaseta et al., On Powers Associated with Sierpinski Numbers, Riesel Numbers and Polignac’s Conjecture (See pages 9-10)
Yves Gallot, A search for some small Brier numbers, 2000.
G. L. Honaker, Jr. and Chris Caldwell, Prime Curios! 6992565235279559197457863
Joe McLean, Brier Numbers [Cached copy]
Carlos Rivera, Problem 29
Carlos Rivera, See here for latest information about progress on this sequence
Eric Weisstein's World of Mathematics, Brier Number
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MATHEMATICA
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lst1 = {}; lst2 = {}; u = {{1, 3}, {2, 5}, {6, 7}, {7, 11}, {11, 13}, {8, 17}, {10, 19}, {23, 31}, {4, 37}, {45, 61}, {41, 73}, {48, 97}, {105, 109}, {33, 151}, {233, 241}, {129, 257}, {2, 331}, {16, 1321}}; p = Times @@ Take[u, All, -1]; q = Flatten[u]; Do[d = p/q[[2*a]]; r = Reduce[d*x == q[[2*a - 1]], x, Modulus -> q[[2*a]]]; If[Length[r] > 0, AppendTo[lst1, d*Last[r]], Abort[]], {a, Length[q]/2}]; c = FromDigits[p]; i = FromDigits@Total[lst1]; n = 0; While[True, i = NestWhile[#/2 &, Abs[i + (-1)^n*c], EvenQ]; n++; If[MemberQ[lst2, i], Print@First@Sort[lst2]; Break[]]; If[n == 360, Break[]]; AppendTo[lst2, i]] (* Arkadiusz Wesolowski, Feb 12 2013 *)
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