A134405 -1 before list of quadruples -2n-1, 2n+2, -2n, 2n+1.

-1, -1, 2, 0, 1, -3, 4, -2, 3, -5, 6, -4, 5, -7, 8, -6, 7, -9, 10, -8, 9, -11, 12, -10, 11, -13, 14, -12, 13, -15, 16, -14, 15, -17, 18, -16, 17, -19, 20, -18, 19, -21, 22, -20, 21, -23, 24, -22, 23, -25, 26, -24, 25, -27, 28, -26, 27, -29, 30, -28, 29, -31

Offset

0,3

Links

Table of n, a(n) for n=0..61.

Index entries for linear recurrences with constant coefficients, signature (-1,0,0,1,1).

Formula

a(n) = (1+(2*n-1)*(-1)^n-4*(-1)^((2*n-1+(-1)^n)/4))/4. - Luce ETIENNE, Sep 04 2016

Mathematica

Join[{-1}, Table[{-2n-1, 2n+2, -2n, 2n+1}, {n, 0, 20}]]//Flatten (* Harvey P. Dale, Apr 19 2023 *)

Crossrefs

Sequence in context: A318602 A004542 A207331 * A091612 A253672 A367562

Adjacent sequences: A134402 A134403 A134404 * A134406 A134407 A134408

Keyword

sign,easy

Author

Paul Curtz, Jan 31 2008

Status

approved