A090133 Expansion of (1+4x)/(1+4x+5x^2).

1, 0, -5, 20, -55, 120, -205, 220, 145, -1680, 5995, -15580, 32345, -51480, 44195, 80620, -543455, 1770720, -4365605, 8608820, -12607255, 7384920, 33496595, -170910980, 516160945, -1210088880, 2259550795, -2987758780, 653281145, 12325669320

Offset: 0

Author

Paul Barry, Nov 21 2003

Keywords

• easy
• sign

References

• D. Cvijovic, J Klinowski, An Application for the Chebyshev Polynomials, Mat. Vesnik 50 (1998) 105-110

Links

• D. Cvijovic and J. Klinowski, An Application for the Chebyshev Polynomials, Mat. Vesnik 50 (1998) 105-110. [broken link]
• Index entries for linear recurrences with constant coefficients, signature (-4,-5).

Crossrefs

Cf. A099456.

Formula

a(n) = Sum_{k=0..n} C(n, k)*(-2)^(n-k)*(-1)^floor(k/2)*(1+(1-(-1)^k)/2).

a(n+1) = (-1)^n * (4*A099456(n) - A099456(n+1)). - Ralf Stephan, Jul 19 2013

Extensions

Better name from Ralf Stephan, Jul 14 2013