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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
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
KEYWORD
nonn
AUTHOR
Barry Wells (wells.barry(AT)gmail.com), Aug 26 2009, Sep 24 2009
STATUS
approved