A173034 Sequence whose G.f is f such that: f(z)=8/(1-2*z)-12/(1-z)+z+5.

1, 5, 20, 52, 116, 244, 500, 1012, 2036, 4084, 8180, 16372, 32756, 65524, 131060, 262132, 524276, 1048564, 2097140, 4194292, 8388596, 16777204, 33554420, 67108852, 134217716, 268435444, 536870900, 1073741812, 2147483636

Offset: 0

Author

Richard Choulet, Feb 07 2010

Keywords

• easy
• nonn

Comments

The Granvik array of A172119 is here written in "square": 1 :: 1 :: 1 :: 1 :: 1 :: 1 :: 1 :: 1 :: 1 :: 1 // 1 :: 2 :: 2 :: 2 :: 2 :: 2 :: 2 :: 2 :: 2 :: 2 // 1 :: 3 :: 4 :: 4 :: 4 :: 4 :: 4 :: 4 :: 4 :: 4 // 1 :: 4 :: 7 :: 8 :: 8 :: 8 :: 8 :: 8 :: 8 :: 8 // This sequence gives the third diagonal under the main diagonal.

Examples

			From 1 + 5*z + 20*z^2 + 52*z^3 + 116*z^4 + 244*z^5 + 500*z^6 + O(z^7) we get a(6)=500.
		

Links

• Index entries for linear recurrences with constant coefficients, signature (3,-2)

Crossrefs

Cf. A172119, A173033.

Formula

a(n) = 8*2^n-12, n>=2. - R. J. Mathar, Apr 20 2011