

A164768


First differences of A003592.


1



1, 2, 1, 3, 2, 6, 4, 5, 7, 8, 10, 14, 16, 20, 25, 3, 32, 40, 50, 6, 64, 80, 100, 12, 113, 15, 160, 200, 24, 226, 30, 320, 400, 48, 452, 60, 565, 75, 800, 96, 904, 120, 1130, 150, 1600, 192, 1808, 240, 2260, 300, 2825, 375, 384, 3616, 480, 4520, 600, 5650
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OFFSET

1,2


COMMENTS

The gaps between the natural numbers whose reciprocals are terminating decimals.


LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..312 from Barry Wells)


FORMULA

a(n) = A003592(n+1)  A003592(n).  Amiram Eldar, Feb 08 2020


EXAMPLE

The first few terms of A003592 are 1, 2, 4, 5, 8, 10, 16 because 1/1, 1/2, 1,4, 1/5, 1/8 etc. terminate and 1/3, 1/6, 1/7, 1/9 etc. repeat. Hence the denominators of the first few terminating decimals are 1, 2, 4, 5, 8, 10, 16 and the first differences between these gives the sequence 1,2,1,3,2,4


CROSSREFS

Cf. A003592.
Sequence in context: A052305 A165045 A337452 * A006208 A026805 A335688
Adjacent sequences: A164765 A164766 A164767 * A164769 A164770 A164771


KEYWORD

nonn


AUTHOR

Barry Wells (wells.barry(AT)gmail.com), Aug 26 2009, Sep 24 2009


STATUS

approved



