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A250268
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Common differences of consecutive prime powers that form a 3-term arithmetic progression.
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0
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1, 1, 1, 1, 2, 2, 2, 2, 3, 2, 6, 12, 2, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 12, 12, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 3, 12, 6, 6, 6, 12, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 12, 6, 6, 6, 6, 6, 6, 6, 12, 6, 6, 6, 12, 12, 6, 12
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OFFSET
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1,5
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COMMENTS
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Subsequence of A057820: a term here corresponds to 3 equal consecutive terms of A057820.
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LINKS
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EXAMPLE
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Common differences of consecutive prime powers in arithmetic progression up to 100:
1: 1 2 3
1: 2 3 4
1: 3 4 5
1: 7 8 9
2: 9 11 13
2: 23 25 27
2: 25 27 29
2: 27 29 31
3: 61 64 67
2: 79 81 83
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PROG
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(PARI) ispp(n) = isprimepower(n) || (n==1);
lista(nn) = {v = select(x->ispp(x), vector(nn, i, i)); for (k=2, #v-1, if (v[k+1] - 2*v[k] + v[k-1] == 0, print1(v[k]-v[k-1], ", ")); ); }
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CROSSREFS
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Cf. A000961 (prime powers), A057820 (common differences of consecutive prime powers).
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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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