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A127397
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a(0)=0; a(n) = smallest positive integer not occurring earlier in the sequence such that a(n-1)+a(n) = j^k, j = any positive integer, k = any integer >= 2.
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3
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0, 1, 3, 5, 4, 12, 13, 14, 2, 6, 10, 15, 17, 8, 19, 30, 34, 47, 53, 11, 16, 9, 7, 18, 31, 33, 48, 52, 29, 20, 44, 37, 27, 22, 42, 39, 25, 24, 40, 41, 23, 26, 38, 43, 21, 28, 36, 45, 55, 66, 59, 62, 63, 58, 67, 54, 46, 35, 65, 56, 69, 75, 50, 71, 57, 64, 61, 60, 68, 32, 49, 51, 70
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OFFSET
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0,3
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LINKS
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MATHEMATICA
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f[n_] := n == 1 || GCD @@ Last /@ FactorInteger[n] > 1; g[l_List] := Block[{k = 1}, While[MemberQ[l, k] || ! f[k + l[[ -1]]], k++ ]; Append[l, k]]; Nest[g, {0}, 73] (* Ray Chandler, Jan 22 2007 *)
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CROSSREFS
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KEYWORD
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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