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A251780 Digital root of A069778(n-1) = n^3 - n^2 + 1, n >= 1. Repeat(1, 6, 3, 7, 6, 6, 4, 6, 9). 1
1, 6, 3, 7, 6, 6, 4, 6, 9, 1, 6, 3, 7, 6, 6, 4, 6, 9, 1, 6, 3, 7, 6, 6, 4, 6, 9, 1, 6, 3, 7, 6, 6, 4, 6, 9, 1, 6, 3, 7, 6, 6, 4, 6, 9, 1, 6, 3, 7, 6, 6, 4, 6, 9, 1, 6, 3, 7, 6, 6, 4, 6, 9, 1, 6, 3, 7, 6, 6, 4, 6, 9, 1, 6, 3, 7, 6, 6, 4, 6, 9, 1, 6, 3, 7, 6, 6, 4, 6, 9, 1, 6, 3, 7, 6, 6, 4, 6, 9, 1, 6, 3, 7, 6, 6, 4, 6, 9 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Periodic with cycle of 9: {1, 6, 3, 7, 6, 6, 4, 6, 9}.
The decimal expansion of 54588823/333333333 = 0.repeat(163766469).
LINKS
Eric Weisstein's World of Mathematics, Digital Root.
FORMULA
a(n) = digital root of n^3 - n^2 + n.
EXAMPLE
For a(3) = 3 because 3^3 - 3^2 + 3 = 27 - 9 + 3 = 21 with digit sum 3 which is also the digital root of 21.
MATHEMATICA
LinearRecurrence[{0, 0, 0, 0, 0, 0, 0, 0, 1}, {1, 6, 3, 7, 6, 6, 4, 6, 9}, 108] (* Ray Chandler, Jul 25 2016 *)
PROG
(PARI) DR(n)=s=sumdigits(n); while(s>9, s=sumdigits(s)); s
for(n=1, 100, print1(DR(abs(n^2-n-n^3)), ", ")) \\ Derek Orr, Dec 30 2014
CROSSREFS
Sequence in context: A246730 A200239 A097676 * A249542 A125123 A133612
KEYWORD
base,nonn,easy
AUTHOR
Peter M. Chema, Dec 08 2014
EXTENSIONS
More terms from Derek Orr, Dec 30 2014
Edited: name changed; formula, comment and example rewritten; digital root link added. - Wolfdieter Lang, Jan 05 2015
STATUS
approved

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Last modified March 28 10:55 EDT 2024. Contains 371241 sequences. (Running on oeis4.)