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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A133464 a(3n)=4^n, a(3n+1)=2*4^n, a(3n+2)=3*4^n.

Original entry on oeis.org

1, 2, 3, 4, 8, 12, 16, 32, 48, 64, 128, 192, 256, 512, 768, 1024, 2048, 3072, 4096, 8192, 12288, 16384, 32768, 49152, 65536, 131072, 196608, 262144, 524288, 786432, 1048576, 2097152, 3145728, 4194304, 8388608, 12582912, 16777216, 33554432
Offset: 0

Views

Author

Paul Curtz, Nov 28 2007

Keywords

Crossrefs

Programs

Formula

O.g.f.: -(1+2*x+3*x^2)/(-1+4*x^3) . 2*a(n)-a(n+1) = abs(A117902(n+1)). - R. J. Mathar, Nov 30 2007
From Reinhard Zumkeller, May 26 2008: (Start)
a(n+1) = a(n) + a(n - n mod 3).
a(n) = A140740(n+3,3). (End)
Sum_{n>=0} 1/a(n) = 22/9. - Amiram Eldar, Jan 21 2022

Extensions

Edited by R. J. Mathar, Nov 30 2007
More terms from Reinhard Zumkeller, May 26 2008

A117901 Inverse of number triangle A117898.

Original entry on oeis.org

1, -1, 1, 0, -2, 1, 0, 3, -2, 1, 0, 0, 0, -1, 1, 0, -6, 3, 0, -2, 1, 0, 12, -6, 0, 3, -2, 1, 0, 0, 0, 0, 0, 0, -1, 1, 0, -24, 12, 0, -6, 3, 0, -2, 1, 0, 48, -24, 0, 12, -6, 0, 3, -2, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 1, 0, -96, 48, 0, -24, 12, 0, -6, 3, 0, -2, 1, 0, 192, -96, 0, 48, -24, 0, 12, -6, 0, 3, -2, 1
Offset: 0

Views

Author

Paul Barry, Apr 01 2006

Keywords

Comments

Row sums are A117902. Diagonal sums are A117903.

Examples

			Triangle begins
1,
-1, 1,
0, -2, 1,
0, 3, -2, 1,
0, 0, 0, -1, 1,
0, -6, 3, 0, -2, 1,
0, 12, -6, 0, 3, -2, 1,
0, 0, 0, 0, 0, 0, -1, 1,
0, -24, 12, 0, -6, 3, 0, -2, 1,
0, 48, -24, 0, 12, -6, 0, 3, -2, 1
		

Formula

G.f.:(2x^6*y^2+x^5*y(2-y)+4x^4(1-y)-x^3(2y^2-3y+4)+x^2*y(y-2)+x(y-1)+1)/((1-4x^3)(1-x^3*y^3))
Showing 1-2 of 2 results.