A134429 a(n) = (-1)^(1 + n) * 2 * ( -1/2 -n + (-1)^((1 + n)*(2 + n)/2)).

3, -5, 3, -5, 11, -13, 11, -13, 19, -21, 19, -21, 27, -29, 27, -29, 35, -37, 35, -37, 43, -45, 43, -45, 51, -53, 51, -53, 59, -61, 59, -61, 67, -69, 67, -69, 75, -77, 75, -77, 83, -85, 83, -85, 91, -93, 91, -93, 99, -101, 99, -101, 107, -109, 107, -109, 115, -117, 115, -117, 123, -125, 123, -125, 131, -133, 131

Offset: 0

Author

Paul Curtz, Jan 31 2008

Keywords

• sign
• easy
• less

Comments

Previous name was: Array read by rows: row n lists 4 terms: k, m, k, m where k = 8n+3 and m = -8n -5.

Links

• B. D. Swan, Table of n, a(n) for n = 0..100000

Crossrefs

Cf. A134314 (first differences).

Programs

Mathematica

Table[With[{k=8n+3,m=-8n-5},{k,m,k,m}],{n,0,30}]//Flatten (* Harvey P. Dale, Jul 18 2018 *)

Formula

a(2*n) + a(2*n+1) = -2.

a(n) = (-1)^(1 + n) * 2 * ( -1/2 -n + (-1)^((1 + n)*(2 + n)/2)). - Gerry Martens, Nov 08 2022

Extensions

Edited by Omar E. Pol, Mar 23 2008

Edited by B. D. Swan (bdswan(AT)gmail.com), Dec 20 2008

New name (using formula from Gerry Martens) from Joerg Arndt, Nov 08 2022