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A145587 a(n)=number of numbers removed in each step of Eratosthenes' sieve for 2^9 0
255, 84, 33, 19, 10, 7, 4, 2 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

COMMENTS

Number of steps in Eratosthenes' sieve for 2^n is A060967(n).

Number of primes less than 2^9 is equal = 2^9 - (sum all of numbers in this sequence) - 1 = A007053(9).

MATHEMATICA

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 = 9; kk = PrimePi[Sqrt[2^nn]]; t3 = f3[2^nn, kk] (*Bob Hanlon*)

CROSSREFS

A006880, A122121, A145532-A145540, A145583-A145592

Sequence in context: A196738 A195859 A145715 * A028526 A132828 A023690

Adjacent sequences:  A145584 A145585 A145586 * A145588 A145589 A145590

KEYWORD

fini,nonn

AUTHOR

Artur Jasinski with assistence from Bob Hanlon (grafix(AT)csl.pl), Oct 14 2008

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Last modified February 17 17:35 EST 2012. Contains 206061 sequences.