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.

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A214292 Triangle read by rows: T(n,k) = T(n-1,k-1) + T(n-1,k), 0 < k < n with T(n,0) = n and T(n,n) = -n.

Original entry on oeis.org

0, 1, -1, 2, 0, -2, 3, 2, -2, -3, 4, 5, 0, -5, -4, 5, 9, 5, -5, -9, -5, 6, 14, 14, 0, -14, -14, -6, 7, 20, 28, 14, -14, -28, -20, -7, 8, 27, 48, 42, 0, -42, -48, -27, -8, 9, 35, 75, 90, 42, -42, -90, -75, -35, -9, 10, 44, 110, 165, 132, 0, -132, -165, -110, -44, -10
Offset: 0

Views

Author

Reinhard Zumkeller, Jul 12 2012

Keywords

Examples

			The triangle begins:
    0:                              0
    1:                            1   -1
    2:                          2   0   -2
    3:                       3    2   -2   -3
    4:                     4    5   0   -5   -4
    5:                  5    9    5   -5   -9   -5
    6:                6   14   14   0  -14  -14   -6
    7:             7   20   28   14  -14  -28  -20   -7
    8:           8   27   48   42   0  -42  -48  -27   -8
    9:        9   35   75   90   42  -42  -90  -75  -35   -9
   10:     10   44  110  165  132   0 -132 -165 -110  -44  -10
   11:  11   54  154  275  297  132 -132 -297 -275 -154  -54  -11  .
		

Crossrefs

Programs

  • Haskell
    a214292 n k = a214292_tabl !! n !! k
    a214292_row n = a214292_tabl !! n
    a214292_tabl = map diff $ tail a007318_tabl
       where diff row = zipWith (-) (tail row) row
  • Mathematica
    row[n_] := Table[Binomial[n, k], {k, 0, n}] // Differences;
    T[n_, k_] := row[n + 1][[k + 1]];
    Table[T[n, k], {n, 0, 10}, {k, 0, n}] // Flatten (* Jean-François Alcover, Jul 31 2018 *)

Formula

T(n,k) = A007318(n+1,k+1) - A007318(n+1,k), 0<=k<=n, i.e. first differences of rows in Pascal's triangle;
T(n,k) = -T(n,k);
row sums and central terms equal 0, cf. A000004;
sum of positive elements of n-th row = A014495(n+1);
T(n,0) = n;
T(n,1) = A000096(n-2) for n > 1; T(n,1) = - A080956(n) for n > 0;
T(n,2) = A005586(n-4) for n > 3; T(n,2) = A129936(n-2);
T(n,3) = A005587(n-6) for n > 5;
T(n,4) = A005557(n-9) for n > 8;
T(n,5) = A064059(n-11) for n > 10;
T(n,6) = A064061(n-13) for n > 12;
T(n,7) = A124087(n) for n > 14;
T(n,8) = A124088(n) for n > 16;
T(2*n+1,n) = T(2*n+2,n) = A000108(n+1), Catalan numbers;
T(2*n+3,n) = A000245(n+2);
T(2*n+4,n) = A002057(n+1);
T(2*n+5,n) = A000344(n+3);
T(2*n+6,n) = A003517(n+3);
T(2*n+7,n) = A000588(n+4);
T(2*n+8,n) = A003518(n+4);
T(2*n+9,n) = A001392(n+5);
T(2*n+10,n) = A003519(n+5);
T(2*n+11,n) = A000589(n+6);
T(2*n+12,n) = A090749(n+6);
T(2*n+13,n) = A000590(n+7).

A124087 9th column of Catalan triangle A009766.

Original entry on oeis.org

1430, 4862, 11934, 25194, 48450, 87210, 149226, 245157, 389367, 600875, 904475, 1332045, 1924065, 2731365, 3817125, 5259150, 7152444, 9612108, 12776588, 16811300, 21912660, 28312548, 36283236, 46142811, 58261125, 73066305, 91051857, 112784399, 138912059
Offset: 15

Views

Author

Zerinvary Lajos, Nov 25 2006

Keywords

Crossrefs

Programs

  • Maple
    [seq(binomial(n,8)-binomial(n,6),n=15..45)];
  • Mathematica
    CoefficientList[Series[(429*z^7 - 3432*z^6 + 11880*z^5 - 23100*z^4 + 27300*z^3 - 19656*z^2 + 8008*z - 1430)/(z - 1)^9, {z, 0, 100}], z] (* Vladimir Joseph Stephan Orlovsky, Jul 16 2011 *)
    Table[Binomial[n,8]-Binomial[n,6],{n,15,60}] (* or *) LinearRecurrence[ {9,-36,84,-126,126,-84,36,-9,1},{1430,4862,11934,25194,48450,87210,149226,245157,389367},30] (* Harvey P. Dale, Apr 15 2017 *)

Formula

a(n) = C(n,8)-C(n,6).
a(n) = A214292(n+15,7). - Reinhard Zumkeller, Jul 12 2012
From Amiram Eldar, Sep 06 2022: (Start)
Sum_{n>=15} 1/a(n) = 12515/11594583.
Sum_{n>=15} (-1)^(n+1)/a(n) = 1942528*log(2)/6435 - 60651032147/289864575. (End)
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