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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A375086 Row sums of A375085.

Original entry on oeis.org

0, 1, 3, 8, 24, 78, 268, 956, 3496, 12998, 48876, 185268, 706456, 2706204, 10404696, 40124792, 155133904, 601113158, 2333671756, 9075266372, 35345525944, 137847053108, 538258923016, 2104101060872, 8233434921904, 32247612071708, 126410623214968, 495918566502536
Offset: 0

Views

Author

Stefano Spezia, Jul 29 2024

Keywords

Crossrefs

Programs

  • Mathematica
    a[n_]:=(2^(n+1)+4^n+4Binomial[2n-2,n-1]-8Binomial[2n-2,n-2]Hypergeometric2F1[1,2-n,1+n,-1])/8; Join[{0,1},Array[a,26,2]]

Formula

a(n) = (2^(n+1) + 4^n + 4*binomial(2*n-2,n-1) - 8*binomial(2*n-2,n-2)*hypergeom([1, 2-n], [1+n], -1))/8 for n > 1.
a(n) ~ A007582(n+2).

A090299 Table T(n,k), n>=0 and k>=0, read by antidiagonals : the k-th column given by the k-th polynomial K_k related to A090285.

Original entry on oeis.org

1, 1, 1, 2, 3, 1, 5, 10, 5, 1, 14, 35, 22, 7, 1, 42, 126, 93, 38, 9, 1, 132, 462, 386, 187, 58, 11, 1, 429, 1716, 1586, 874, 325, 82, 13, 1, 1430, 6435, 6476, 3958, 1686, 515, 110, 15, 1, 4862, 24310, 26333, 17548, 8330, 2934, 765, 142, 17, 1
Offset: 0

Views

Author

Philippe Deléham, Jan 25 2004

Keywords

Comments

Read as a number triangle, this is the Riordan array (c(x),x/sqrt(1-4x)) where c(x) is the g.f. of A000108. - Paul Barry, May 16 2005

Examples

			row n=0 : 1, 1, 2, 5, 14, 42, 132, 429, ... see A000108.
row n=1 : 1, 3, 10, 35, 126, 462, 1716, 6435, ... see A001700.
row n=2 : 1, 5, 22, 93, 386, 1586, 6476, ... see A000346.
row n=3 : 1, 7, 38, 187, 874, 3958, 17548, ... see A000531.
row n=4 : 1, 9, 58, 325, 1686, 8330, 39796, ... see A018218.
		

Crossrefs

Other rows : A029887, A042941, A045724, A042985, A045492. Columns : A000012, A005408. Row n is the convolution of the row (n-j) with A000984, A000302, A002457, A002697 (first term omitted), A002802, A038845, A020918, A038846, A020920 for j=1, 2, ..9 respectively.

Formula

T(n, k) = K_k(n)= Sum_{j>=0} A090285(k, j)*2^j*binomial(n, j). T(n, 1) = 2*n+1. T(n, 2) = 2*A028387(n).

Extensions

Corrected by Alford Arnold, Oct 18 2006

A204451 2*A014335 - A203578. Difference of the exponential convolution of A000045 (Fibonacci) with itself and the corresponding exponential half-convolution.

Original entry on oeis.org

0, 0, 0, 3, 8, 35, 75, 371, 888, 3891, 9445, 40755, 102323, 426803, 1091167, 4469555, 11625960, 46805811, 123364443, 490156851, 1306737465, 5132989235, 13816838695, 53753361203, 145912841523, 562912506675, 1539304050375, 5894896300851, 16225419029303, 61732155503411, 170909837010835
Offset: 0

Views

Author

Wolfdieter Lang, Jan 16 2012

Keywords

Comments

See A203578 for the exponential (or binomial) half-convolution of A000045 (Fibonacci). The present sequence has to be added to this sequence in order to obtain the (full) exponential convolution 2*A014335.

Crossrefs

Formula

a(n) = sum(binomial(n,k)*F(k)*F(n-k), k=floor(n/2)+1..n), n>=0, with the Fibonacci numbers A000045(n).
E.g.f.: exp(x)*(cosh((2*phi-1)*x)-1)/5 - (BesselI(0,2*phi*x) + BesselI(0,2*(phi-1)*x) - 2*BesselI(0,2*I*x))/10. See the e.g.f. of A203578, also for phi and BesselI.
Bisection: a(2*k) =((2^(2*k) - binomial(2*k,k))*L(2*k)/2 - (1 - (-1)^k*binomial(2*k,k)))/5 and a(2*k+1) = (2^(2*k)*L(2*k+1) - 1)/5 = A203578(2*k), k>=0, with the Lucas numbers L(n)= A000032(n). Compare with A203578. See A000346(k-1), with A000346(-1)=0, for (2^(2*k) - binomial(2*k,k))/2, k>=0.

A355635 Triangle read by rows. Row n gives the coefficients of Product_{k=0..n-1} (x - binomial(n-1,k)) expanded in decreasing powers of x, with row 0 = {1}.

Original entry on oeis.org

1, 1, -1, 1, -2, 1, 1, -4, 5, -2, 1, -8, 22, -24, 9, 1, -16, 93, -238, 256, -96, 1, -32, 386, -2180, 5825, -6500, 2500, 1, -64, 1586, -19184, 117561, -345600, 407700, -162000, 1, -128, 6476, -164864, 2229206, -15585920, 51583084, -64538880, 26471025
Offset: 0

Views

Author

Thomas Scheuerle, Jul 11 2022

Keywords

Comments

Without signs the triangle of elementary symmetric functions of the terms binomial(n,j), j=0..n.

Examples

			The triangle begins:
  1;
  1,  -1;
  1,  -2,   1;
  1,  -4,   5,    -2;
  1,  -8,  22,   -24,    9;
  1, -16,  93,  -238,  256,   -96;
  1, -32, 386, -2180, 5825, -6500, 2500;
  ...
Row 4: x^4 - 8*x^3 + 22*x^2 - 24*x + 9 = (x-1)*(x-4)*(x-6)*(x-4)*(x-1).
		

Crossrefs

Cf. A001142 (right diagonal unsigned).

Programs

  • PARI
    T(n, k) = polcoeff(prod(m=0, n, (x-binomial(n-1, m))), n-k+1);

Formula

T(n, 0) = 1.
T(n, 1) = -2^(n-1), for n > 0.
T(n, 2) = A000346(n-2), for n > 1.
T(n, 3) = -A025131(n-1), for n > 1.
T(n, 4) = A025133(n-1), for n > 1.
T(n, n) = (-1)^n*A001142(n-1), for n > 0.
T(n+1, n) = (-1)^n*A025134(n).
T(n+2, n) = (-1)^n*A025135(n).
Previous Showing 91-94 of 94 results.