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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A115127 Second (k=2) triangle of numbers related to totally asymmetric exclusion process (case alpha=1, beta=1).

Original entry on oeis.org

3, 6, 7, 10, 16, 19, 15, 30, 47, 56, 21, 50, 95, 146, 174, 28, 77, 170, 311, 471, 561, 36, 112, 280, 586, 1043, 1562, 1859, 45, 156, 434, 1015, 2044, 3564, 5291, 6292, 55, 210, 642, 1652, 3682, 7204, 12363, 18226, 21658, 66, 275, 915, 2562, 6230, 13392, 25623
Offset: 2

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Author

Wolfdieter Lang, Jan 13 2006

Keywords

Comments

This is the second floor (k=2) of a pyramid of numbers, called X(1,1,k=2,n,m) with n>=m+1>=2. One could use offset n>=1 and add a zero main diagonal.
The column sequences give for n>=m+1 and m=1..7: A000217, A005581, A024191, A115129, A115130, A115132, A115133.
The diagonal sequences give for M:=n-m=1..3: A071716, A071726, A115134.

Examples

			[3];[6,7];[10,16,19];[15,30,47,56];...
Main diagonal (n-m=1) example: a(3,2)= 7 = 5 + 2 because
A115126(3,2)=5 and A115126(2,2)=2.
Subdiagonal (n-m>1) example: a(4,2)= 16 = 9 + 7 because
A115126(4,2)=9 and a(3,2)=7.
		

Crossrefs

Row sums give A115128.

Formula

a(n,m)= b(n,m) + b(n-1,m) with b(n,m):=A115126(n,m) if n=m+1 (main diagonal), A115126(n,m) + a(n,-1,m) if n>m+1 (subdiagonals) and 0 if n

A115130 Partial sums of A005557.

Original entry on oeis.org

42, 174, 471, 1043, 2044, 3682, 6230, 10038, 15546, 23298, 33957, 48321, 67340, 92134, 124012, 164492, 215322, 278502, 356307, 451311, 566412, 704858, 870274, 1066690, 1298570, 1570842, 1888929, 2258781, 2686908, 3180414, 3747032
Offset: 0

Author

Wolfdieter Lang, Jan 13 2006

Keywords

Crossrefs

Cf. A115129 (fourth column of A115127).

Programs

  • Mathematica
    Accumulate[LinearRecurrence[{6,-15,20,-15,6,-1},{42,132,297,572,1001,1638},40]] (* or *) LinearRecurrence[{7,-21,35,-35,21,-7,1},{42,174,471,1043,2044,3682,6230},40] (* Harvey P. Dale, Feb 22 2024 *)

Formula

G.f.: (42-120*x+135*x^2-70*x^3+14*x^4)/(1-x)^7.
a(n)=A115127(n+5, 5), n>=1.
Showing 1-2 of 2 results.