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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A164965 Cumulative sums of A010892.

Original entry on oeis.org

1, 2, 2, 1, 0, 0, 1, 2, 2, 1, 0, 0, 1, 2, 2, 1, 0, 0, 1, 2, 2, 1, 0, 0, 1, 2, 2, 1, 0, 0, 1, 2, 2, 1, 0, 0, 1, 2, 2, 1, 0, 0, 1, 2, 2, 1, 0, 0, 1, 2, 2, 1, 0, 0, 1, 2, 2, 1, 0, 0, 1, 2, 2, 1, 0, 0, 1, 2, 2, 1, 0, 0, 1, 2, 2, 1, 0, 0, 1, 2, 2, 1, 0, 0
Offset: 0

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Author

Mark Dols, Sep 02 2009

Keywords

Crossrefs

Programs

  • Mathematica
    Table[-Floor[1/6 (-4 + n)] - Floor[1/6 (-3 + n)] + Floor[1/6 (-1 + n)] + Floor[n/6], {n, 0, 100}] (* John M. Campbell, Dec 23 2016 *)
    LinearRecurrence[{2,-2,1},{1,2,2},100] (* Harvey P. Dale, Jul 17 2020 *)

Formula

G.f.: 1/((1 - x)*(1 - x + x^2)). - Philippe Deléham, Oct 11 2011
a(n) = a(n-1) - a(n-2) + 1. - Arkadiusz Wesolowski, Jun 08 2013
a(n) = -floor((n - 4)/6) - floor((n - 3)/6) + floor((n - 1)/6) + floor(n/6). - John M. Campbell, Dec 23 2016
E.g.f.: cosh(x) + 2*exp(x/2)*sin(sqrt(3)*x/2)/sqrt(3) + sinh(x). - Stefano Spezia, Feb 20 2023

Extensions

Offset corrected by John M. Campbell, Dec 23 2016

A320508 T(n,k) = binomial(n - k - 1, k), 0 <= k < n, and T(n,n) = (-1)^n, triangle read by rows.

Original entry on oeis.org

1, 1, -1, 1, 0, 1, 1, 1, 0, -1, 1, 2, 0, 0, 1, 1, 3, 1, 0, 0, -1, 1, 4, 3, 0, 0, 0, 1, 1, 5, 6, 1, 0, 0, 0, -1, 1, 6, 10, 4, 0, 0, 0, 0, 1, 1, 7, 15, 10, 1, 0, 0, 0, 0, -1, 1, 8, 21, 20, 5, 0, 0, 0, 0, 0, 1, 1, 9, 28, 35, 15, 1, 0, 0, 0, 0, 0, -1, 1, 10, 36
Offset: 0

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Author

Keywords

Comments

Differs from A164925 in signs.
The n-th row consists of the coefficients in the expansion of (-x)^n + (((1 + sqrt(1 + 4*x))/2)^n -((1 - sqrt(1 + 4*x))/2)^n )/sqrt(1 + 4*x).
The coefficients in the expansion of Sum_{j=0..floor((n - 1)/2)} T(n,k)*x^(n - 2*j - 1) yield the n-th row in A168561, the coefficients of the n-th Fibonacci polynomial.
Row n sums up to Fibonacci(n) + (-1)^n (A008346).

Examples

			Triangle begins:
    1;
    1, -1;
    1,  0,  1;
    1,  1,  0, -1;
    1,  2,  0,  0,  1;
    1,  3,  1,  0,  0, -1;
    1,  4,  3,  0,  0,  0, 1;
    1,  5,  6,  1,  0,  0, 0, -1;
    1,  6, 10,  4,  0,  0, 0,  0, 1;
    1,  7, 15, 10,  1,  0, 0,  0, 0, -1;
    1,  8, 21, 20,  5,  0, 0,  0, 0,  0, 1;
    1,  9, 28, 35, 15,  1, 0,  0, 0,  0, 0, -1;
    ...
		

Crossrefs

Programs

  • Mathematica
    Table[Table[Binomial[n - k - 1, k], {k, 0, n}], {n, 0, 12}]//Flatten
  • Maxima
    create_list(binomial(n - k - 1, k), n, 0, 12, k, 0, n);

Formula

G.f.: 1/((1 + x*y)*(1 - y - x*y^2)).
E.g.f.: exp(-x*y) + (exp(y*(1 + sqrt(1 + 4*x))/2) - exp(y*(1 - sqrt(1 + 4*x))/2))/sqrt(1 + 4*x).
T(n,1) = A023443(n).
Showing 1-2 of 2 results.