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A073051 Least k such that Sum(i=1..k, prime_i + prime_{i+2} - 2prime_{i+1} ) = 2n+1. 2
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; refs; listen; history; internal format)
OFFSET

1,2

COMMENTS

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

EXAMPLE

a(3) = 8 because 1+0+2-2+2-2+2+2 = 5 and (5+1)/2 = 3.

MATHEMATICA

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

CROSSREFS

Cf. A001223, A000230.

Sequence in context: A148774 A093537 A180621 * A183930 A183922 A068602

Adjacent sequences:  A073048 A073049 A073050 * A073052 A073053 A073054

KEYWORD

nonn

AUTHOR

Robert G. Wilson v (rgwv(AT)rgwv.com), Aug 15 2002

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Last modified February 17 16:13 EST 2012. Contains 206050 sequences.