A254823 - OEIS

A254823

Number of length n 1..(4+1) arrays with every leading partial sum divisible by 2, 3 or 5

4, 16, 54, 166, 500, 1557, 5316, 19292, 69536, 248613, 893091, 3146780, 10584619, 34064054, 108011322, 350399707, 1186298040, 4158109604, 14813200901, 52859389574, 186599450347, 643953634665, 2160180481888, 7086155229600

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OFFSET

1,1

COMMENTS

Column 4 of A254827

LINKS

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

FORMULA

Empirical: a(n) = 3*a(n-1) -6*a(n-2) +10*a(n-3) -15*a(n-4) +21*a(n-5) -27*a(n-6) +150*a(n-7) +1910*a(n-8) +10081*a(n-9) +23355*a(n-10) +32804*a(n-11) +30881*a(n-12) +20836*a(n-13) +10122*a(n-14) +3593*a(n-15) +939*a(n-16) +180*a(n-17) +21*a(n-18) +a(n-19)

EXAMPLE

Some solutions for n=4

..5....4....5....4....3....3....2....4....2....5....3....2....3....4....2....4

..5....2....4....5....2....1....4....1....2....4....1....4....5....1....4....4

..2....3....1....5....1....5....2....1....4....5....2....3....2....1....2....1

..4....3....4....1....4....5....2....4....1....4....3....1....5....3....4....5

CROSSREFS

Sequence in context: A121159 A358232 A239032 * A134968 A238419 A267227

Adjacent sequences: A254820 A254821 A254822 * A254824 A254825 A254826

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 08 2015

STATUS

approved