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Search: id:A145535
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| A145535 |
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a(n)=number of numbers removed in each step of Eratosthenes' sieve for 8! |
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+0
2
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| 20159, 6719, 2687, 1535, 836, 642, 454, 381, 297, 223, 204, 170, 154, 146, 134, 119, 108, 103, 92, 84, 81, 76, 70, 64, 56, 53, 51, 47, 45, 42, 36, 32, 30, 28, 23, 21, 18, 16, 15, 12, 8, 6, 5, 3, 2, 1
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Number of steps in Eratosthenes' sieve for n! is A133228(n).
Number of primes less than 8! is equal = 8!-(sum all numbers in this sequence)-1 = A003604(8).
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MATHEMATICA
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f3[k_Integer?Positive, i_Integer?Positive] := Module[{f, m, r, p}, p = Transpose[{r = Range[2, i], Prime[r]}]; f[x_] := Catch[Fold[If[Mod[x, #2[[2]]] == 0, Throw[m[ #2[[1]]] = m[ #2[[1]]] + 1], #1] &, If[Mod[x, 2] == 0, Throw[m[1] = m[1] + 1]], p]]; Table[m[n] = -1, {n, i}]; f /@ Range[k]; Table[m[n], {n, i}]]; nn = 8; kk = PrimePi[Sqrt[nn! ]]; t3 = f3[nn!, kk] (*Bob Hanlon*)
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CROSSREFS
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A003604, A133228, A145532-A145540
Sequence in context: A081866 A090072 A035926 this_sequence A109479 A003808 A011786
Adjacent sequences: A145532 A145533 A145534 this_sequence A145536 A145537 A145538
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KEYWORD
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fini,nonn
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AUTHOR
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Artur Jasinski with assistence from Bob Hanlon (grafix(AT)csl.pl), Oct 14 2008
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