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 1-5 of 5 results.

A111954 a(n) = A000129(n) + (-1)^n.

Original entry on oeis.org

1, 0, 3, 4, 13, 28, 71, 168, 409, 984, 2379, 5740, 13861, 33460, 80783, 195024, 470833, 1136688, 2744211, 6625108, 15994429, 38613964, 93222359, 225058680, 543339721, 1311738120, 3166815963, 7645370044, 18457556053, 44560482148, 107578520351
Offset: 0

Views

Author

Creighton Dement, Aug 23 2005

Keywords

Comments

a(n) + a(n+1) = A001333(n+1). Inverse binomial transform of A007070 (with prepended 1). Inverse invert transform of A077995.
Floretion Algebra Multiplication Program, FAMP Code: -4ibasejseq[J*D] with J = - .25'i + .25'j + .5'k - .25i' + .25j' + .5k' - .5'kk' - .25'ik' - .25'jk' - .25'ki' - .25'kj' - .5e and D = + .5'i - .25'j + .25'k + .5i' - .25j' + .25k' - .5'ii' - .25'ij' - .25'ik' - .25'ji' - .25'ki' - .5e

Links

Crossrefs

Cf. A000129, A001333, A111955, A111956, A007070, A077995.

Programs

  • Mathematica
    LinearRecurrence[{1,3,1},{1,0,3},40] (* Harvey P. Dale, Nov 24 2014 *)

Formula

a(n) = a(n-1) + 3*a(n-2) + a(n-3), n >= 3.
G.f.: (x-1)/((x+1)*(x^2+2*x-1)).
a(n) = (sqrt(2)/4)*((1 + sqrt(2))^n - (1 - sqrt(2))^n) + (-1)^n.
E.g.f.: cosh(x) - sinh(x) + exp(x)*sinh(sqrt(2)*x)/sqrt(2). - Stefano Spezia, May 26 2024

A111955 a(n) = A078343(n) + (-1)^n.

Original entry on oeis.org

0, 1, 4, 7, 20, 45, 112, 267, 648, 1561, 3772, 9103, 21980, 53061, 128104, 309267, 746640, 1802545, 4351732, 10506007, 25363748, 61233501, 147830752, 356895003, 861620760, 2080136521, 5021893804, 12123924127, 29269742060, 70663408245
Offset: 0

Views

Author

Creighton Dement, Aug 25 2005

Keywords

Comments

This sequence is a companion sequence to A111954 (compare formula / program code). Three other companion sequences (i.e., they are generated by the same floretion given in the program code) are A105635, A097076 and A100828.
Floretion Algebra Multiplication Program, FAMP Code: 4kbasejseq[J*D] with J = - .25'i + .25'j + .5'k - .25i' + .25j' + .5k' - .5'kk' - .25'ik' - .25'jk' - .25'ki' - .25'kj' - .5e and D = + .5'i - .25'j + .25'k + .5i' - .25j' + .25k' - .5'ii' - .25'ij' - .25'ik' - .25'ji' - .25'ki' - .5e. (an initial term 0 was added to the sequence)

Links

Crossrefs

Cf. A078343, A000129, A001333, A111954, A111956, A007070, A077995, A100828, A097076, A105635, A048655.

Programs

  • Mathematica
    LinearRecurrence[{1,3,1},{0,1,4},40] (* Harvey P. Dale, Mar 12 2015 *)

Formula

a(n) + a(n+1) = A048655(n).
a(n) = a(n-1) + 3*a(n-2) + a(n-3), n >= 3; a(n) = (-1/4*sqrt(2)+1)*(1-sqrt(2))^n + (1/4*sqrt(2)+1)*(1+sqrt(2))^n - (-1)^n;
G.f.: -x*(1+3*x) / ( (1+x)*(x^2+2*x-1) ). - R. J. Mathar, Oct 02 2012
E.g.f.: cosh(x) - exp(x)*cosh(sqrt(2)*x) - sinh(x) + 3*exp(x)*sinh(sqrt(2)*x)/sqrt(2). - Stefano Spezia, May 26 2024

A182412 Triangle T(n,k), read by rows, given by (1, 2, -2, 0, 0, 0, 0, 0, 0, 0, ...) DELTA (1, 2, -1, 0, 0, 0, 0, 0, 0, 0, ...) where DELTA is the operator defined in A084938.

Original entry on oeis.org

1, 1, 1, 3, 6, 3, 5, 17, 19, 7, 11, 48, 80, 60, 17, 21, 119, 270, 308, 177, 41, 43, 290, 823, 1256, 1087, 506, 99, 85, 677, 2321, 4447, 5147, 3601, 1411, 239, 171, 1556, 6234, 14360, 20806, 19424, 11416, 3864, 577
Offset: 0

Views

Author

Philippe Deléham, Apr 27 2012

Keywords

Comments

Antidiagonal sums are in A077995.

Examples

			Triangle begins
1
1, 1
3, 6, 3
5, 17, 19, 7
11, 48, 80, 60, 17
21, 119, 270, 308, 177, 41
43, 290, 823, 1256, 1087, 506, 99
85, 677, 2321, 4447, 5147, 3601, 1411, 239

Crossrefs

Cf. A001045, A001333, A077995,

Formula

G.f.: (1-y*x)/(1-(1+2*y)*x-(2+3*y+y^2)*x^2)
T(n,k) = T(n-1,k) + 2*T(n-1,k-1) + 2*T(n-2,k) + 3*T(n-2,k-1) + T(n-2,k-2), T(0,0) = T(1,0) = T(1,1) = 1, T(2,0) = T(2,2) = 3, T(2,1) = 6 and T(n,k) = 0 if k<0 or if k>n.
T(n,n) = A001333(n), T(n,0) = A001045(n+1).
Sum_{k, 0<=k<=n} T(n,k)*(-1)^k = A000007(n).

A207327 Riordan array (1, x*(1+x)^2/(1-x)).

Original entry on oeis.org

1, 0, 1, 0, 3, 1, 0, 4, 6, 1, 0, 4, 17, 9, 1, 0, 4, 32, 39, 12, 1, 0, 4, 48, 111, 70, 15, 1, 0, 4, 64, 240, 268, 110, 18, 1, 0, 4, 80, 432, 769, 530, 159, 21, 1, 0, 4, 96, 688, 1792, 1905, 924, 217, 24, 1, 0, 4
Offset: 0

Views

Author

Philippe Deléham, Feb 17 2012

Keywords

Comments

Triangle T(n,k), read by rows, given by (0, 3, -5/3, 4/15, -3/5, 0, 0, 0, 0, 0, 0, 0, ...) DELTA (1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, ...) where DELTA is the operator defined in A084938.
Row sums are A077995(n).

Examples

			Triangle begins :
1
0, 1
0, 3, 1
0, 4, 6, 1
0, 4, 17, 9, 1
0, 4, 32, 39, 12, 1
0, 4, 48, 111, 70, 15, 1
0, 4, 64, 240, 268, 110, 18, 1
0, 4, 80, 432, 769, 530, 159, 21, 1
0, 4, 96, 688, 1792, 1905, 924, 217, 24, 1
0, 4, 112, 1008, 3584, 5503, 3999, 1477, 284, 27, 1
0, 4, 128, 1392, 6400, 13440, 13842, 7483, 2216, 360, 30, 1

Crossrefs

Cf. Diagonals : A000012, A008585, A022266, A000007, A113311

Formula

T(2*n,n) = A119259(n).
G.f.: (1-x)/(1-(1+y)*x-2*y*x^2-y*x^3).
T(n,k) = T(n-1,k) + T(n-1,k-1) + 2*T(n-2,k-1) + T(n-3,k-1), T(0,0) = 1, T(1,0) = 0.

A210636 Riordan array ((1-x)/(1-2*x-x^2), x*(1+x)/(1-2*x-x^2)).

Original entry on oeis.org

1, 1, 1, 3, 4, 1, 7, 13, 7, 1, 17, 40, 32, 10, 1, 41, 117, 124, 60, 13, 1, 99, 332, 437, 286, 97, 16, 1, 239, 921, 1447, 1193, 553, 143, 19, 1, 577, 2512, 4584, 4556, 2682, 952, 198, 22, 1, 1393, 6761, 14048, 16336, 11666, 5282, 1510, 262, 25, 1
Offset: 0

Views

Author

Philippe Deléham, Mar 26 2012

Keywords

Comments

Triangle T(n,k), 0<=k<=n, read by rows, given by (1, 2, -1, 0, 0, 0, 0, 0, 0, 0, ...) DELTA (1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, ...) where DELTA is the operator defined in A084938.
Product of A122542 and A007318 (Pascal's triangle) as lower triangular matrices .

Examples

			Triangle begins :
1
1, 1
3, 4, 1
7, 13, 7, 1
17, 40, 32, 10, 1
41, 117, 124, 60, 13, 1
99, 332, 437, 286, 97, 16, 1
239, 921, 1447, 1193, 553, 143, 19, 1
577, 2512, 4584, 4556, 2682, 952, 198, 22, 1
1393, 6761, 14048, 16336, 11666, 5282, 1510, 262, 25, 1

Crossrefs

Cf. Columns :A001333, A119915, Diagonals : A000012, A016777, Antidiagonal sums : A077995

Formula

T(n,k) = 2*T(n-1,k) + T(n-1,k-1) + T(n-2,k) + T(n-2,k-1), T(0,0) = T(1,0) = T(1,1) = 1 and T(n,k) = 0 if k<0 or if k>n.
G.f.: (1-x)/(1-2*x-y*x-x^2-y*x^2).
Sum_{k, 0<=k<=n} T(n,k)*x^k = A000007(n), A001333(n), A104934(n), A122958(n), A122690(n), A091928(n) for x = -1, 0, 1, 2, 3, 4 respectively.
Showing 1-5 of 5 results.

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