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 1-3 of 3 results.

A131437 (A000012 * A131436) + (A131436 * A000012) - A000012.

Original entry on oeis.org

1, 3, 5, 7, 9, 13, 15, 17, 21, 29, 31, 33, 37, 45, 61, 63, 65, 69, 77, 93, 125, 127, 129, 133, 141, 157, 189, 253, 255, 257, 261, 269, 285, 317, 381, 509, 511, 513, 517, 525, 541, 573, 637, 765, 1021, 1023, 1025, 1029, 1037, 1053, 1085, 1149, 1277, 1533, 2045
Offset: 1

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Author

Gary W. Adamson, Jul 11 2007

Keywords

Comments

Left column = 2^n - 1; right border = A036563, 2^(n+1) - 3: (1, 5, 13, 29, 61, 125, ...). Row sums = A131438: (1, 8, 29, 82, 207, 492, 1129, ...).

Examples

			First few rows of the triangle are:
1;
3, 5;
7, 9, 13;
15, 17, 21, 29;
31, 33, 37, 45, 61;
63, 65, 69, 77, 93, 125;
...
		

Crossrefs

Programs

Formula

(A000012 * A131436) + (A131436 * A000012) - A000012; as infinite lower triangular matrices.

Extensions

Corrected by R. J. Mathar, Sep 24 2011

A131438 (2+n)*2^n-2-3*n.

Original entry on oeis.org

1, 8, 29, 82, 207, 492, 1129, 2534, 5603, 12256, 26589, 57306, 122839, 262100, 557009, 1179598, 2490315, 5242824, 11009989, 23068610, 48234431, 100663228, 209715129, 436207542, 905969587
Offset: 1

Views

Author

Gary W. Adamson, Jul 11 2007

Keywords

Comments

Row sums of triangle A131437.

Examples

			a(3) = 19 = sum of row 3 terms of triangle A131437: (7 + 9 + 13).
		

Crossrefs

Formula

Binomial transform of A131439.
G.f.: -x*(-1-2*x+6*x^2) / ( (2*x-1)^2*(x-1)^2 ). - R. J. Mathar, Sep 24 2011

Extensions

Definition replaced by formula. - R. J. Mathar, Sep 24 2011

A131439 Inverse binomial transform of A131438 (assuming zero offset in both sequences).

Original entry on oeis.org

1, 7, 14, 18, 22, 26, 30, 34, 38, 42, 46, 50, 54, 58, 62, 66, 70, 74, 78, 82, 86, 90, 94, 98, 102, 106, 110, 114, 118, 122, 126, 130, 134, 138, 142, 146, 150, 154, 158, 162, 166, 170, 174, 178, 182
Offset: 1

Views

Author

Gary W. Adamson, Jul 11 2007

Keywords

Comments

Conjecture: The sequence appears to be (1, 7, ...) followed by 4k + 14; k=0,1,2,...; thus: (1, 7, 14, 18, 22, 26, ...).
Inverse binomial transform of this sequence = (1, 6, 1, -4, 7, -10, 13, -16, 19, -22, ...).

Examples

			(1, 3, 3, 1) dot (1, 7, 14, 18) = 82 = A131438(4).
		

Crossrefs

Formula

a(n) = 2*a(n-1) - a(n-2) for n>4. G.f.: -x*(x+1)*(3*x^2-4*x-1) / (x-1)^2. [Colin Barker, Jan 06 2013]
Showing 1-3 of 3 results.