OFFSET
1,3
COMMENTS
Row 3 of A184257.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..998
FORMULA
Empirical: a(n) = 2*a(n-1) - a(n-2) + a(n-27) - 2*a(n-28) + a(n-29).
Empirical g.f.: x*(1 - x + x^2 - x^3 + x^5 - x^6 + x^8 + x^18 - x^20 + x^21 - x^23 + x^24 + x^26 - 2*x^27 + x^28) / ((1 - x)^3*(1 + x + x^2)*(1 + x^3 + x^6)*(1 + x^9 + x^18)). - Colin Barker, Apr 12 2018
EXAMPLE
All solutions for n=5:
..3....0
..3....0
..4....5
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 10 2011
STATUS
approved