OFFSET
1,2
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = a(n-1) + a(n-30) - a(n-31).
Empirical g.f.: x*(1 + x + x^2 + x^3 + x^4 + x^6 + x^7 + x^8 + x^10 + x^12 + x^13 + x^14 + x^16 + x^18 + x^19 + x^20 + x^22 + x^23 + x^24 + x^25 + x^26 + x^28) / ((1 - x)^2*(1 + x)*(1 - x + x^2)*(1 + x + x^2)*(1 - x + x^2 - x^3 + x^4)*(1 + x + x^2 + x^3 + x^4)*(1 - x + x^3 - x^4 + x^5 - x^7 + x^8)*(1 + x - x^3 - x^4 - x^5 + x^7 + x^8)). - Colin Barker, Dec 18 2018
EXAMPLE
All solutions for n=4:
..2....5....3....4
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 08 2015
STATUS
approved