

A060460


Consider the final n decimal digits of 2^j for all values of j. They are periodic. Sequence gives position (or phase) of the maximal value seen in these n digits.


1



3, 12, 53, 254, 1255, 6256, 31257, 156258, 781259, 3906260, 19531261, 97656262, 488281263, 2441406264, 12207031265, 61035156266, 305175781267, 1525878906268, 7629394531269, 38146972656270, 190734863281271
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OFFSET

0,1


LINKS

Table of n, a(n) for n=0..20.
Index entries for sequences related to final digits of numbers


FORMULA

a(1)=3, a[n]=5*a(n1)[3+4*(n1)] a(2)=5*3[3+4*0]=153=12, etc..
2*5^n + n + 1.


EXAMPLE

n=2, the last 2 digits of powers of 2 have the period {2,4,8,16,32,64,28,56,12,24,48,96,92,84,68,36,72,44,88,76,52,4,8,16,32} displayed in A000855. Last n digits of 2^a(n) are predictable if maximal values of periods are known. The maximum is 96 and it occurs at 2^12=4096. So a(2)=12.


CROSSREFS

Cf. A000079, A000855, A005054, A060458.
Sequence in context: A110122 A307412 A302188 * A306525 A293131 A120983
Adjacent sequences: A060457 A060458 A060459 * A060461 A060462 A060463


KEYWORD

base,nonn


AUTHOR

Labos Elemer, Apr 09 2001


STATUS

approved



