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A228217 Number of second differences of arrays of length n+2 of numbers in 0..7 1
29, 519, 7309, 88215, 951049, 9399615, 86929081, 766106895, 6537612649, 54701587935, 452558355481, 3719467815855, 30436607366089, 248242046141055, 2019169299698041, 16385984911571535, 132716292890482729 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 7 of A228218

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = 15*a(n-1) -56*a(n-2) for n>15

EXAMPLE

Some solutions for n=4

.-8....0...-8....1....4..-11....3....7..-10...-1...-4....4...-2....8...-3...-9

.13...-2...-1....5...-3....7....0...-4....3...10....8...-2...-8...-4....5...11

-12...-3....4...-7...-4...-3...-5....8...-1..-13....0...-3....7...-8....3...-1

..8....9....2....4....1....3...-2..-11....6...12..-10...-3....7...11...-3...-4

CROSSREFS

Sequence in context: A225969 A211560 A333064 * A305315 A225899 A028180

Adjacent sequences:  A228214 A228215 A228216 * A228218 A228219 A228220

KEYWORD

nonn

AUTHOR

R. H. Hardin Aug 16 2013

STATUS

approved

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Last modified September 23 15:43 EDT 2020. Contains 337310 sequences. (Running on oeis4.)