cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-2 of 2 results.

A187397 Expansion of -2*x^4 *(3*x^13 +2*x^12 +x^11 -6*x^10 -10*x^9 -6*x^8 +x^7 +7*x^6 +5*x^5 -x^4 -8*x^3 -11*x^2 -8*x -5) / ((x -1)^4 *(x +1)^2 *(x^2 +1)^2 *(x^2 +x +1)^2).

Original entry on oeis.org

0, 0, 0, 0, 10, 16, 22, 36, 54, 66, 92, 122, 156, 196, 240, 288, 366, 426, 490, 590, 698, 780, 904, 1036, 1176, 1326, 1484, 1650, 1874, 2060, 2254, 2512, 2782, 3006, 3300, 3606, 3924, 4256, 4600, 4956, 5398, 5782, 6178, 6666, 7170, 7608, 8144
Offset: 0

Views

Author

Sean A. Irvine, Mar 23 2011

Keywords

Comments

In contrast, the number of distinct lines passing through 4 or more points in an n X n grid is given by 0, 0, 0, 10, 16, 22, 44, 74, 92, 154, 232, 326, 436, 562, 704, 998, 1268,.. = A018808(n) -A018809(n) -A018810(n) = A225606(n) -A018810(n). - David W. Wilson, Aug 05 2013

Crossrefs

Programs

  • Mathematica
    CoefficientList[ Series[ 2x^4 (5 + 8x + 11x^2 + 8x^3 + x^4 - 5x^5 - 7x^6 - x^7 + 6x^8 + 10x^9 + 6x^10 - x^11 - 2x^12 - 3x^13)/((-1 + x)^4 (1 + x)^2 (1 + x^2)^2 (1 + x + x^2)^2), {x, 0, 43}], x] (* or *) LinearRecurrence[{0, 0, 2, 2, 0, -1, -4, -1, 0, 2, 2, 0, 0, -1}, {10, 16, 22, 36, 54, 66, 92, 122, 156, 196, 240, 288, 366, 426}, 40] (* Robert G. Wilson v, Feb 17 2014 *)

Extensions

Definition replaced with Colin Barker's g.f. by R. J. Mathar, Aug 06 2013
Offset changed from 1 to 0 and a(0)=0 added by Vincenzo Librandi, Feb 19 2014

A187062 Expansion of 2*x^2 *(4 +7*x +5*x^2 -x^3 -4*x^4 +6*x^6 +4*x^7 -x^8 -2*x^9) / ((1+x)^2 *(1+x+x^2)^2 *(1-x)^4) .

Original entry on oeis.org

0, 0, 8, 14, 26, 42, 64, 90, 134, 172, 232, 300, 378, 464, 584, 690, 834, 990, 1160, 1342, 1574, 1784, 2048, 2328, 2626, 2940, 3320, 3670, 4090, 4530, 4992, 5474, 6038, 6564, 7176, 7812, 8474, 9160, 9944, 10682, 11522, 12390, 13288, 14214
Offset: 1

Views

Author

Sean A. Irvine, Mar 21 2011

Keywords

Crossrefs

Programs

  • Mathematica
    CoefficientList[Series[ 2x^2 (4 + 7x + 5x^2 - x^3 - 4x^4 + 6x^6 + 4x^7 - x^8 - 2x^9)/((1 + x)^2 (1 + x + x^2)^2 (x - 1)^4), {x, 0, 43}], x]  (* or *) LinearRecurrence[ {0, 2, 2, -1, -4, -1, 2, 2, 0, -1}, {8, 14, 26, 42, 64, 90, 134, 172, 232, 300}, 42] (* Robert G. Wilson v, Feb 17 2014 *)

Formula

a(n) = 2*a(n-2) + 2*a(n-3) - a(n-4) - 4*a(n-5) - a(n-6) + 2*a(n-7) + 2*a(n-8) - a(n-10) .

Extensions

Name replaced by L. Edson Jeffery's definition. R. J. Mathar, Aug 06 2013
Showing 1-2 of 2 results.