A007380 Number of 5th-order maximal independent sets in path graph.

1, 2, 1, 3, 1, 4, 2, 5, 4, 6, 7, 7, 11, 9, 16, 13, 22, 20, 29, 31, 38, 47, 51, 69, 71, 98, 102, 136, 149, 187, 218, 258, 316, 360, 452, 509, 639, 727, 897, 1043, 1257, 1495, 1766, 2134, 2493, 3031, 3536, 4288, 5031, 6054, 7165, 8547, 10196

Offset: 1

Author

N. J. A. Sloane, Mira Bernstein

Keywords

• nonn

References

• N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
• R. Yanco and A. Bagchi, "K-th order maximal independent sets in path and cycle graphs", J. Graph Theory, submitted, 1994.

Links

• R. Yanco, Letter and Email to N. J. A. Sloane, 1994
• R. Yanco and A. Bagchi, K-th order maximal independent sets in path and cycle graphs, Unpublished manuscript, 1994. (Annotated scanned copy)

Formula

Apparently, a(n) = a(n-2) + a(n-7) with g.f. -x*(1+2*x+x^3+x^5+x^6)/(-1+x^2+x^7). - R. J. Mathar, Oct 30 2009

a(n) = T(2, 7, n + 7) where T(a, b, n) = Sum_{a*x+b*y = n, x >= 0, y >= 0} binomial(x+y, y). - Sean A. Irvine, Jan 02 2018

Extensions

More terms from Sean A. Irvine, Jan 02 2018