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A183955 Number of strings of numbers x(i=1..4) in 0..n with sum i^2*x(i) equal to n*16. 2
1, 1, 4, 8, 14, 21, 32, 48, 61, 82, 108, 139, 172, 210, 256, 311, 365, 427, 500, 582, 666, 759, 864, 982, 1097, 1228, 1372, 1529, 1688, 1860, 2048, 2253, 2457, 2677, 2916, 3172, 3430, 3705, 4000, 4316, 4629, 4966, 5324, 5703, 6084, 6486, 6912, 7363, 7813, 8287 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Row 4 of A183953.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..200

FORMULA

Empirical: a(n) = 2*a(n-1) - a(n-2) + a(n-4) - 2*a(n-5) + a(n-6) + a(n-16) - 2*a(n-17) + a(n-18) - a(n-20) + 2*a(n-21)-a(n-22).

Empirical g.f.: x*(1 - x + 3*x^2 + x^3 + x^4 + 2*x^5 + x^6 + 4*x^7 - 5*x^8 + 7*x^9 + x^10 + 5*x^12 - 3*x^13 + 3*x^14 + 4*x^15 - 4*x^16 + 4*x^17 - x^19 + 2*x^20 - x^21) / ((1 - x)^4*(1 + x)^2*(1 + x^2)^2*(1 + x^4)*(1 + x^8)). - Colin Barker, Apr 07 2018

EXAMPLE

All solutions for n=3:

..2....3....0....1

..3....1....0....1

..2....1....0....3

..1....2....3....1

CROSSREFS

Cf. A183953.

Sequence in context: A027924 A006578 A122224 * A299896 A312700 A312701

Adjacent sequences:  A183952 A183953 A183954 * A183956 A183957 A183958

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 08 2011

STATUS

approved

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Last modified September 18 23:16 EDT 2021. Contains 347548 sequences. (Running on oeis4.)