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A105930 Starting position of the n-th prime in the almost-natural numbers sequence A007376. 0
2, 3, 5, 7, 12, 16, 24, 28, 36, 48, 52, 64, 72, 76, 84, 96, 108, 112, 124, 132, 136, 148, 156, 168, 184, 193, 199, 211, 217, 229, 271, 283, 301, 307, 337, 343, 361, 379, 391, 409, 427, 433, 463, 469, 481, 487, 523, 559, 571, 577, 589, 607, 613, 643, 661, 679 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,1

COMMENTS

Prime number positions in the "counting digits": write the natural numbers as an infinite sequence of digits, starting at the left. a(n) is the subscript (i.e. the position in this sequence of "counting digits") of the first digit of the n-th prime.

LINKS

Table of n, a(n) for n=2..57.

EXAMPLE

a(6)=16 because the sixth prime (13) appears at the 16th (and 17th) position in the "counting digits": 123456789101112-13-141516

MATHEMATICA

f[n_] := Block[{d = Floor[ Log[10, n] + 1]}, d(n - 1) - Sum[9i*10^(d - i - 1), {i, d - 1}] + 1]; Table[ f[ Prime[n]], {n, 56}] (* Robert G. Wilson v, Apr 30 2005 *)

CROSSREFS

Cf. A007376, A103575.

Sequence in context: A113623 A308868 A078912 * A122622 A266775 A024790

Adjacent sequences:  A105927 A105928 A105929 * A105931 A105932 A105933

KEYWORD

base,easy,nonn

AUTHOR

Alexandre Wajnberg, Apr 26 2005

EXTENSIONS

Edited by Robert G. Wilson v, Apr 30 2005

STATUS

approved

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Last modified September 18 11:36 EDT 2020. Contains 337169 sequences. (Running on oeis4.)