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.

A253381 Triangle read by rows: T(n,k) appears in the transformation Sum_{k=0..n} (k+1)*x^k = Sum_{k=0..n} T(n,k)*(x+2k)^k.

Original entry on oeis.org

1, -3, 2, -3, -22, 3, -3, 122, -69, 4, -3, -518, 891, -156, 5, -3, 1882, -8709, 3444, -295, 6, -3, -6182, 71931, -57036, 9785, -498, 7, -3, 18906, -530181, 789684, -241095, 23022, -777, 8, -3, -54822, 3598587, -9661260, 4919865, -783378, 47607, -1144, 9, -3, 152538, -22943493, 107911860, -87977415, 21896622, -2129673, 89576, -1611, 10
Offset: 0

Views

Author

Derek Orr, Dec 30 2014

Keywords

Comments

Consider the transformation 1 + 2x + 3x^2 + 4x^3 + ... + (n+1)*x^n = T(n,0)*(x+0)^0 + T(n,1)*(x+2)^1 + T(n,2)*(x+4)^2 + ... + T(n,n)*(x+2n)^n for n >= 0.

Examples

			From - _Wolfdieter Lang_, Jan 12 2015: (Start)
The triangle T(n,k) starts:
n\k  0      1         2         3         4        5        6     7     8  9 ...
0:   1
1:  -3      2
2:  -3    -22         3
3:  -3    122       -69         4
4:  -3   -518       891      -156         5
5:  -3   1882     -8709      3444      -295        6
6:  -3  -6182     71931    -57036      9785     -498        7
7:  -3  18906   -530181    789684   -241095    23022     -777     8
8:  -3 -54822   3598587  -9661260   4919865  -783378    47607 -1144     9
9 : -3 152538 -22943493 107911860 -87977415 21896622 -2129673 89576 -1611 10
... Reformatted.
----------------------------------------------------------------------------------
n = 3: 1 + 2*x + 3*x^2 + 4*x^3 = -3*(x+0)^0 + 122*(x+2)^1 - 69*(x+4)^2 + 4* (x+6)^3. (End)
		

Crossrefs

Cf. A247236.

Programs

  • PARI
    T(n,k) = (k+1)-sum(i=k+1,n,(2*i)^(i-k)*binomial(i,k)*T(n,i))
    for(n=0,10,for(k=0,n,print1(T(n,k),", ")))

Formula

T(n,n) = n+1, for n >= 0.
T(n,n-1) = n*(1 - 2*n - 2*n^2), for n >= 1.
T(n,n-2) = (n-1)*(2*n^4-2*n^3-6*n^2+2*n+1), for n >= 2.
T(n,n-3) = (2-n)*(4*n^6-24*n^5+26*n^4+54*n^3-72*n^2+9)/3, for n >= 3.

Extensions

Edited; - Wolfdieter Lang, Jan 12 2015