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 1-4 of 4 results.

A053209 Row sums of A051598.

Original entry on oeis.org

1, 5, 14, 32, 68, 140, 284, 572, 1148, 2300, 4604, 9212, 18428, 36860, 73724, 147452, 294908, 589820, 1179644, 2359292, 4718588, 9437180, 18874364, 37748732, 75497468, 150994940, 301989884, 603979772, 1207959548, 2415919100
Offset: 0

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Author

Asher Auel, Dec 14 1999

Keywords

Crossrefs

Programs

  • Magma
    I:=[5,14]; [1] cat [n le 2 select I[n] else 3*Self(n-1) - 2*Self(n-2): n in [1..30]]; // G. C. Greubel, Sep 03 2018
    
  • Magma
    R:=PowerSeriesRing(Integers(), 30); Coefficients(R!( (1+x)^2)/((1-x)*(1-2*x))); // Marius A. Burtea, Oct 15 2019
  • Mathematica
    Join[{1}, LinearRecurrence[{3, -2}, {5, 14}, 50]] (* G. C. Greubel, Sep 03 2018 *)
  • PARI
    m=30; v=concat([5,14], vector(m-2)); for(n=3, m, v[n] = 3*v[n-1] -2*v[n-2]); concat([1], v) \\ G. C. Greubel, Sep 03 2018
    

Formula

a(0) = 1, a(1) = 5, a(n+1) = 2*a(n) + 4, for n >= 1.
a(n) = 9*2^(n-1) - 4, n >= 1.
a(n) = 4*n + Sum[i = 0, n - 1] a(i). - Jon Perry, Nov 20 2012
a(n) = A048491(n)/2, n>0. - Philippe Deléham, Apr 15 2013
G.f.: (1+x)^2/((1-x)*(1-2*x)). - Philippe Deléham, Apr 15 2013
a(n) = 3*a(n-1) - 2*a(n-2) with a(0)=1, a(1)=5, a(2)=14. - Philippe Deléham, Apr 15 2013
E.g.f.: (1 - 8*exp(x) + 9*exp(2*x))/2. - Stefano Spezia, Sep 28 2022

A202873 Symmetric matrix based on (1,3,7,15,31,...), by antidiagonals.

Original entry on oeis.org

1, 3, 3, 7, 10, 7, 15, 24, 24, 15, 31, 52, 59, 52, 31, 63, 108, 129, 129, 108, 63, 127, 220, 269, 284, 269, 220, 127, 255, 444, 549, 594, 594, 549, 444, 255, 511, 892, 1109, 1214, 1245, 1214, 1109, 892, 511, 1023, 1788, 2229, 2454, 2547, 2547, 2454
Offset: 1

Views

Author

Clark Kimberling, Dec 26 2011

Keywords

Comments

Let s=(1,3,7,15,31,...) and let T be the infinite square matrix whose n-th row is formed by putting n-1 zeros before the terms of s. Let T' be the transpose of T. Then A202873 represents the matrix product M=T'*T. M is the self-fusion matrix of s, as defined at A193722. See A202767 for characteristic polynomials of principal submatrices of M.

Examples

			Northwest corner:
1.....3.....7...15...31.....63
3....10....24...52...108...220
7....24....59..129...269...549
15...52...129..284...594..1214
31...108..269..594..1245..2547
		

Crossrefs

Cf. A202767.

Programs

  • Mathematica
    s[k_] := -1 + 2^k;
    U = NestList[Most[Prepend[#, 0]] &, #, Length[#] - 1] &[Table[s[k], {k, 1, 15}]];
    L = Transpose[U]; M = L.U; TableForm[M]
    m[i_, j_] := M[[i]][[j]];
    Flatten[Table[m[i, n + 1 - i], {n, 1, 12}, {i, 1, n}]]
    f[n_] := Sum[m[i, n], {i, 1, n}] + Sum[m[n, j], {j, 1, n - 1}]
    Table[f[n], {n, 1, 12}]
    Table[Sqrt[f[n]], {n, 1, 12}] (* A000295, Eulerian *)
    Table[m[1, j], {j, 1, 12}]    (* A000225 *)
    Table[m[2, j], {j, 1, 12}]    (* A053208 *)

A358125 Triangle read by rows: T(n, k) = 2^n - 2^(n-k-1) - 2^k, 0 <= k <= n-1.

Original entry on oeis.org

0, 1, 1, 3, 4, 3, 7, 10, 10, 7, 15, 22, 24, 22, 15, 31, 46, 52, 52, 46, 31, 63, 94, 108, 112, 108, 94, 63, 127, 190, 220, 232, 232, 220, 190, 127, 255, 382, 444, 472, 480, 472, 444, 382, 255, 511, 766, 892, 952, 976, 976, 952, 892, 766, 511, 1023, 1534, 1788, 1912, 1968, 1984, 1968, 1912, 1788, 1534, 1023
Offset: 1

Views

Author

Keywords

Comments

T(n, k) is the expanded number of player-reduced static games within an n-player two-strategy game scenario in which one player (the "standpoint") faces a specific combination of other players' individual strategies with the possibility of anti-coordination between them -- the total number of such combinations is 2^(n-1). The value of k represents the number of other players who (are expected to) agree on one of the two strategies in S, while the other n-k-1 choose the other strategy; the standpoint player is not included.

Examples

			Triangle begins:
  0;
  1,     1;
  3,     4,    3;
  7,    10,   10,    7;
  15,   22,   24,   22,   15;
  31,   46,   52,   52,   46,   31;
  63,   94,  108,  112,  108,   94,   63;
 127,  190,  220,  232,  232,  220,  190,  127;
 255,  382,  444,  472,  480,  472,  444,  382,  255;
 511,  766,  892,  952,  976,  976,  952,  892,  766,  511;
1023, 1534, 1788, 1912, 1968, 1984, 1968, 1912, 1788, 1534, 1023;
2047, 3070, 3580, 3832, 3952, 4000, 4000, 3952, 3832, 3580, 3070, 2047;
  ...
		

Crossrefs

Column k=0 gives A000225(n-1).
Column k=1 gives A033484(n-2).
Column k=2 gives A053208(n-3).

Programs

  • Maple
    T := n -> seq(2^n - 2^(n - k - 1) - 2^k, k = 0 .. n - 1);
    seq(T(n), n=1..12);
  • Mathematica
    T[n_, k_] := 2^n - 2^(n - k - 1) - 2^k; Table[T[n, k], {n, 1, 11}, {k, 0, n - 1}] // Flatten (* Amiram Eldar, Dec 20 2022 *)

Formula

T(n, k) = 2^n - 2^(n-k-1) - 2^k.
Sum_{k=0..n-1} T(n,k)*binomial(n-1,k) = 2*A005061(n-1)

A053207 Rows of triangle formed using Pascal's rule except begin n-th row with n and end it with n+1.

Original entry on oeis.org

0, 1, 2, 3, 3, 4, 5, 6, 7, 6, 7, 11, 13, 13, 8, 9, 18, 24, 26, 21, 10, 11, 27, 42, 50, 47, 31, 12, 13, 38, 69, 92, 97, 78, 43, 14, 15, 51, 107, 161, 189, 175, 121, 57, 16, 17, 66, 158, 268, 350, 364, 296, 178, 73, 18, 19, 83, 224, 426, 618, 714, 660, 474, 251, 91, 20
Offset: 0

Views

Author

Asher Auel, Dec 13 1999

Keywords

Examples

			Triangle begins:
  0;
  1,  2;
  3,  3,  4;
  5,  6,  7,  6;
  7, 11, 13, 13, 8;
  ...
		

Crossrefs

Row sums give A053208.
Cf. A007318 (Pascal's triangle)
Showing 1-4 of 4 results.