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A209202
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Values of the difference d for 3 primes in geometric-arithmetic progression with the minimal sequence {3*3^j + j*d}, j = 0 to 2.
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10
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2, 8, 10, 20, 22, 28, 38, 50, 52, 62, 70, 92, 98, 100, 118, 122, 128, 140, 142, 170, 202, 218, 220, 230, 232, 248, 260, 268, 272, 302, 308, 328, 350, 358, 380, 392, 400, 430, 440, 470, 478, 482, 512, 532, 538, 548, 562, 568, 598, 632, 638, 650, 700, 710, 730
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OFFSET
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1,1
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COMMENTS
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A geometric-arithmetic progression of primes is a set of k primes (denoted by GAP-k) of the form p r^j + j d for fixed p, r and d and consecutive j. Symbolically, for r = 1, this sequence simplifies to the familiar primes in arithmetic progression (denoted by AP-k). The computations were done without any assumptions on the form of d. Primality requires d to be even and coprime to 3.
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LINKS
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EXAMPLE
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d = 8 then {3*3^j + j*d}, j = 0 to 2, is {3, 17, 43}, which is 3 primes in geometric-arithmetic progression.
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MATHEMATICA
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p = 3; gapset3d = {}; Do[If[PrimeQ[{p, p*p + d, p*p^2 + 2*d}] == {True, True, True}, AppendTo[gapset3d, d]], {d, 0, 1000, 2}]; gapset3d
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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