This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A075419 a(n)=Sum((-1)^(i+Floor(n/2))C(2i+e),(i=0,..,Floor(n/2))), where C(n) are reflected tribonacci numbers (A073145). 1
 3, -1, -4, 6, -1, -7, 12, -8, -9, 31, -32, -10, 75, -95, 8, 160, -261, 111, 308, -682, 487, 505, -1676, 1656, 527, -3857, 4984, -602, -8237, 13825, -6192, -15872, 35891, -26209, -25556, 87654, -88305, -24903, 200860, -264264, 38503, 426623, -729392, 341270, 814747, -1885407, 1411928, 1288224 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS a(n) is the convolution of C(n) with the sequence (1,0,-1,0,1,0,-1,0,....) A056594. LINKS FORMULA a(n)=-a(n-1)-2a(n-2)-a(n-4)+a(n-5), a(0)=3, a(1)=-1, a(2)=-4, a(3)=6, a(4)=-1. Ogf (3 + 2x + x^2)/(1 + x + 2x^2 + x^4 - x^5). MATHEMATICA CoefficientList[Series[(3 + 2x + x^2)/(1 + x + 2x^2 + x^4 - x^5), {x, 0, 50}], x] CROSSREFS Cf. A073145. Sequence in context: A108285 A207619 A209694 * A060922 A143790 A135611 Adjacent sequences:  A075416 A075417 A075418 * A075420 A075421 A075422 KEYWORD easy,sign AUTHOR Mario Catalani (mario.catalani(AT)unito.it), Sep 17 2002 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
Recent Additions | More pages | Superseeker | Maintained by The OEIS Foundation Inc.

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