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.

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

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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]

A131436 Triangle read by rows, (n-1) zeros followed by 2^n - 1.

Original entry on oeis.org

1, 0, 3, 0, 0, 7, 0, 0, 0, 15, 0, 0, 0, 0, 31, 0, 0, 0, 0, 0, 63, 0, 0, 0, 0, 0, 0, 127, 0, 0, 0, 0, 0, 0, 0, 255, 0, 0, 0, 0, 0, 0, 0, 0, 511, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1023, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2047, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4095, 0, 0
Offset: 1

Views

Author

Gary W. Adamson, Jul 11 2007

Keywords

Examples

			First few rows of the triangle are:
1;
0, 3;
0, 0, 7;
0, 0, 0, 15;
0, 0, 0, 0, 31;
...
		

Crossrefs

Programs

  • Mathematica
    Flatten[Table[{PadRight[{},n-1,0],2^n-1},{n,20}]] (* Harvey P. Dale, May 23 2012 *)

Formula

2*A059268(n)-A059268(n+1). - Paul Curtz, Jul 03 2008

Extensions

More terms from Harvey P. Dale, May 23 2012

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

Views

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
Showing 1-3 of 3 results.