A072335 - OEIS

This site is supported by donations to The OEIS Foundation.

A072335

Expansion of 1/((1-x^2)*(1-4*x+x^2)).

1, 4, 16, 60, 225, 840, 3136, 11704, 43681, 163020, 608400, 2270580, 8473921, 31625104, 118026496, 440480880, 1643897025, 6135107220, 22896531856, 85451020204, 318907548961, 1190179175640, 4441809153600, 16577057438760, 61866420601441, 230888624967004 (list; graph; refs; listen; history; internal format)

	OFFSET	`0,2`
	LINKS	`N. J. A. Sloane, Transforms` `Index entries for sequences related to Chebyshev polynomials.`
	FORMULA	`a(n) = 1/12((7-4sqrt(3))(2-sqrt(3))^n+(7+4sqrt(3))(2+sqrt(3))^n-3+(-1)^n). Recurrence: a(n) = 4a(n-1)-4*a(n-3)+a(n-4).` `a(n)=sum{k=0..floor(n/2), U(n-2k, 2)} - Paul Barry (pbarry(AT)wit.ie), Nov 15 2003`
	CROSSREFS	`EULER transform of A072279 (with its initial 1 omitted).` `A001353(n)^2 is a bisection of a(n).` `Sequence in context: A089932 A120926 A128650 * A081161 A032106 A047097` `Adjacent sequences: A072332 A072333 A072334 * A072336 A072337 A072338`
	KEYWORD	`nonn`
	AUTHOR	`N. J. A. Sloane (njas(AT)research.att.com), Jul 15 2002`

Content is available under The OEIS End-User License Agreement .

Last modified February 15 20:26 EST 2012. Contains 205852 sequences.