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Search: id:A073051
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| A073051 |
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Least k such that Sum(i=1..k, prime_i + prime_{i+2} - 2prime_{i+1} ) = 2n+1. |
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3
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| 1, 3, 8, 23, 33, 45, 29, 281, 98, 153, 188, 262, 366, 428, 589, 737, 216, 1182, 3301, 2190, 1878, 1830, 7969, 3076, 3426, 2224, 3792, 8027, 4611, 4521, 3643, 8687, 14861, 12541, 15782, 3384, 34201, 19025, 17005, 44772, 23282, 38589, 14356
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Also, least k such that 2n = A001223[k-1] = Prime[k+1] - Prime[k], where Prime[k] = A001223[n]. - Alexander Adamchuk (alex(AT)kolmogorov.com), Jul 30 2006
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EXAMPLE
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a(3) = 8 because 1+0+2-2+2-2+2+2 = 5 and (5+1)/2 = 3.
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MATHEMATICA
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NextPrim[n_Integer] := Block[{k = n + 1}, While[ !PrimeQ[k], k++ ]; k]; a = Table[0, {50}]; s = 0; k = 1; p = 0; q = 2; r = 3; While[k < 10^6, p = q; q = r; r = NextPrim[q]; s = s + p + r - 2q; If[s < 101 && a[[(s + 1)/2]] == 0, a[[(s + 1)/2]] = k]; k++ ]; a
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CROSSREFS
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Cf. A001223, A000230.
Sequence in context: A148773 A148774 A093537 this_sequence A068602 A027212 A027236
Adjacent sequences: A073048 A073049 A073050 this_sequence A073052 A073053 A073054
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KEYWORD
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nonn
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AUTHOR
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Robert G. Wilson v (rgwv(AT)rgwv.com), Aug 15 2002
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