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A007546
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Number of steps to compute n-th prime in PRIMEGAME (fast version).
(Formerly M5074)
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7
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19, 69, 280, 707, 2363, 3876, 8068, 11319, 19201, 36866, 45551, 75224, 101112, 117831, 152025, 215384, 293375, 327020, 428553, 507519, 555694, 700063, 808331, 989526, 1273490, 1434366, 1530213, 1710923, 1818254, 2019962, 2833089, 3104685, 3546320, 3720785
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OFFSET
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1,1
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REFERENCES
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D. Olivastro, Ancient Puzzles. Bantam Books, NY, 1993, p. 21.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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LINKS
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MAPLE
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with(numtheory): f:= proc(n) local l, b, d; l:= sort([divisors (n)[]]); b:= l[nops(l)-1]; n-1 +(6*n+2)*(n-b) +2*add(floor(n/d), d=b..n-1) end: a:= proc(n) option remember; `if`(n=1, f(2), a(n-1) +add(f(i), i=ithprime(n-1)+1..ithprime(n))) end: seq(a(n), n=1..40); # Alois P. Heinz, Aug 12 2009
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MATHEMATICA
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f[n_] := Module[{l, b, d}, l = Divisors [n]; b = l[[-2]]; n-1 + (6*n+2)*(n-b) + 2*Sum[Floor[n/d], {d, b, n-1}]]; a[n_] := a[n] = If[n == 1, f[2], a[n-1] + Sum[f[i], {i, Prime[n-1]+1, Prime[n]}]]; Table[a[n], {n, 1, 32}] (* Jean-François Alcover, Oct 04 2013, translated from Alois P. Heinz's Maple program *)
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CROSSREFS
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KEYWORD
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easy,nonn,nice
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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