

A105930


Starting position of the nth prime in the almostnatural 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
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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 nth 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": 12345678910111213141516


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



