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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A151930 First differences of A001316.

Original entry on oeis.org

1, 0, 2, -2, 2, 0, 4, -6, 2, 0, 4, -4, 4, 0, 8, -14, 2, 0, 4, -4, 4, 0, 8, -12, 4, 0, 8, -8, 8, 0, 16, -30, 2, 0, 4, -4, 4, 0, 8, -12, 4, 0, 8, -8, 8, 0, 16, -28, 4, 0, 8, -8, 8, 0, 16, -24, 8, 0, 16, -16, 16, 0, 32, -62, 2, 0, 4, -4, 4, 0, 8, -12, 4, 0, 8, -8, 8, 0, 16, -28, 4, 0, 8, -8, 8, 0, 16, -24, 8, 0, 16, -16, 16, 0, 32
Offset: 0

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Author

N. J. A. Sloane, Aug 10 2009

Keywords

Comments

Net increase in number of ON cells at generation n of 1-D CA using Rule 90.

Crossrefs

Programs

  • Maple
    nmax := 94: A001316 := n -> if n<=-1 then 0 else 2^add(i, i=convert(n, base, 2)) fi: for p from 0 to ceil(log[2](nmax))+1 do for n from 0 to nmax/(p+2)+1 do a((2*n+1)*2^p-1) := (2-2^p) * A001316(n) od: od: seq(a(n), n=0..nmax); # Johannes W. Meijer, Jan 25 2013

Formula

a((2*n+1)*2^p-1) = (2-2^p) * A001316(n), p >= 0 and n >=0. - Johannes W. Meijer, Jan 25 2013
G.f.: -1/x + ((1 - x)/x)*Product_{k>=0} (1 + 2*x^(2^k)). - Ilya Gutkovskiy, Feb 28 2017

A167275 Row sums of triangle A167274 (a variant of Gould's sequence A001316).

Original entry on oeis.org

1, 4, 4, 8, 4, 8, 8, 16, 4, 8, 8, 16, 8, 16, 16, 32, 4, 8, 8, 16, 8, 16, 16, 32
Offset: 0

Views

Author

Gary W. Adamson & Mats Granvik, Oct 31 2009

Keywords

Examples

			a(3) = 8 = 2*A001316 = 2*4. a(3) = 8 = (1 + 3 + 3 + 1); where (1, 3, 3, 1) = row 3 of triangle A167274.
		

Crossrefs

Formula

Given Gould's sequence, A001316, (1, 2, 2, 4, 2, 4, 4, 8,...); for a(n)>1,
a(n) = 2*A001316(n).

A256257 6 times numbers of Gould's sequence A001316.

Original entry on oeis.org

6, 12, 12, 24, 12, 24, 24, 48, 12, 24, 24, 48, 24, 48, 48, 96, 12, 24, 24, 48, 24, 48, 48, 96, 24, 48, 48, 96, 48, 96, 96, 192, 12, 24, 24, 48, 24, 48, 48, 96, 24, 48, 48, 96, 48, 96, 96, 192, 24, 48, 48, 96, 48, 96, 96, 192, 48, 96, 96, 192, 96, 192, 192, 384, 12, 24, 24, 48, 24, 48, 48, 96, 24, 48, 48, 96, 48, 96, 96, 192
Offset: 0

Views

Author

Omar E. Pol, Mar 20 2015

Keywords

Comments

Also, number of triangular cells turned ON at (n+1)-st stage in the structure of A256256.
First differences of A256256.

Examples

			Written as an irregular triangle in which the row lengths are the terms of A011782, the sequence begins:
6;
12;
12, 24;
12, 24, 24, 48;
12, 24, 24, 48, 24, 48, 48, 96;
12, 24, 24, 48, 24, 48, 48, 96, 24, 48, 48, 96, 48, 96, 96, 192;
...
		

Crossrefs

Formula

a(n) = 6*A001316(n) = 3*A117973(n) = 2*A160713(n).
a(n) = 12*A048896(n-1), n >= 1.

A368655 Binomial transform of Gould's sequence (A001316).

Original entry on oeis.org

1, 3, 7, 17, 39, 85, 181, 387, 839, 1829, 3953, 8391, 17461, 35759, 72559, 146921, 298631, 611733, 1265185, 2641351, 5555729, 11735571, 24798755, 52219493, 109213269, 226322799, 464125219, 941694917, 1891879215, 3769497853, 7465462669, 14735667195, 29070011399
Offset: 0

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Author

Joseph M. Shunia, Jan 02 2024

Keywords

Comments

Consider the multivariate polynomial quotient ring K'n = Z[x_1, x_2, x_3, ..., x_n]/I where I = <x_1^2 - P_1, x_2^2 - P_2, ..., x_n^2 - P_n> is an ideal in Z[x_1, x_2, x_3, ..., x_n]. Here, each polynomial P_i = -2x_i + x{i+1} for 0 < i <= n, with x_{n+1} assumed to be 1. In this ring, every variable x_i for 0 < i <= n satisfies the recursive relation x_i^2 = -2x_i + x_{i+1}. The n-th term of this sequence is obtained by expanding the polynomial (2 + x_1)^n within the ring K'_n and evaluating at x_1 = x_2 = ... = x_n = 1. For a detailed explanation and proof, refer to Shunia's paper under links.

Crossrefs

Cf. A000120, A001316 (Gould's sequence).

Programs

  • Mathematica
    Table[Sum[Binomial[n, k] * 2^DigitCount[k, 2, 1], {k, 0, n}], {n, 0, 32}] (* Vaclav Kotesovec, Apr 02 2024 *)
  • PARI
    {a(n) = sum(k=0, n, binomial(n,k) * 2^hammingweight(k))};
    
  • Sage
    def a(n):
        R = PolynomialRing(ZZ, n, 'x')
        x = R.gens()
        I_list = [x[i]^2 - (-2*x[i] + x[i+1]) if i < n-1 else x[i]^2 for i in range(n)]
        I = R.ideal(I_list)
        K_n = R.quotient(I, 'x')
        p_n = K_n((x[0]+2)^n)
        subs_dict = {x[i]: 1 for i in range(n)}
        a_n = p_n.lift().subs(subs_dict)
        return a_n # Joseph M. Shunia, Mar 22 2024

Formula

a(n) = Sum_{k=0..n} binomial(n,k)*A001316(k).
a(n) = Sum_{k=0..n} binomial(n,k)*2^(A000120(k)).

A130831 Irregular triangle read by rows: row(n) contains the first A001146(n) terms of A001316.

Original entry on oeis.org

1, 2, 1, 2, 2, 4, 1, 2, 2, 4, 2, 4, 4, 8, 2, 4, 4, 8, 4, 8, 8, 16, 1, 2, 2, 4, 2, 4, 4, 8, 2, 4, 4, 8, 4, 8, 8, 16, 2, 4, 4, 8, 4, 8, 8, 16, 4, 8, 8, 16, 8, 16, 16, 32, 2, 4, 4, 8, 4, 8, 8, 16, 4, 8, 8, 16, 8, 16, 16, 32, 4, 8, 8, 16, 8, 16, 16, 32, 8, 16, 16, 32, 16, 32, 32, 64, 2, 4, 4, 8, 4, 8, 8, 16
Offset: 1

Views

Author

Roger L. Bagula, Aug 20 2007

Keywords

Comments

The n-th row of the triangle consists of the first A001146(n) terms of A001316. - Benjamin Heiland, Dec 12 2011

Examples

			Triangle begins:
{1, 2},
{1, 2, 2, 4},
{1, 2, 2, 4, 2, 4, 4, 8, 2, 4, 4, 8, 4, 8, 8, 16}
...
		

Crossrefs

Extensions

Edited by N. J. A. Sloane, Jun 07 2008
New name using Benjamin Heiland's comment, Joerg Arndt, May 11 2023

A160110 Numerators of |Bernoulli(n)*Gould(n)| for even n, (Gould A001316).

Original entry on oeis.org

1, 1, 1, 2, 1, 10, 1382, 28, 3617, 87734, 349222, 3418052, 472728182, 34212412, 94997844116, 68926730208040, 7709321041217, 5155375716734, 52630543106106954746, 11719975655366236, 522165436992898244102
Offset: 0

Views

Author

Peter Luschny, May 02 2009

Keywords

Comments

A001897 give the denominators of |Bernoulli(n)*Gould(n)| for even n, also the denominators of the cosecant numbers.

Crossrefs

Cf. A001897.

Programs

  • Maple
    b := n -> bernoulli(n)*2^add(i,i=convert(n,base,2));
    a := n -> numer(abs(b(2*n)));
  • Mathematica
    G[n_] := Sum[Mod[Binomial[n, k], 2], {k, 0, n}]; (* A001316 *) Table[Abs[BernoulliB[n]*G[n]], {n, 0, 20}][[1 ;; -1 ;; 2]]//Numerator (* G. C. Greubel, Sep 25 2018 *)

A160713 3 times numbers of Gould's sequence: a(n) = A001316(n)*3.

Original entry on oeis.org

3, 6, 6, 12, 6, 12, 12, 24, 6, 12, 12, 24, 12, 24, 24, 48, 6, 12, 12, 24, 12, 24, 24, 48, 12, 24, 24, 48, 24, 48, 48, 96, 6, 12, 12, 24, 12, 24, 24, 48, 12, 24, 24, 48, 24, 48, 48, 96, 12, 24, 24, 48, 24, 48, 48, 96, 24, 48, 48, 96, 48, 96, 96, 192, 6, 12, 12, 24, 12, 24, 24, 48
Offset: 0

Views

Author

Omar E. Pol, May 25 2009

Keywords

Examples

			From _Omar E. Pol_, Aug 09 2009: (Start)
If written as a triangle:
3;
6;
6,12;
6,12,12,24;
6,12,12,24,12,24,24,48;
6,12,12,24,12,24,24,48,12,24,24,48,24,48,48,96;
6,12,12,24,12,24,24,48,12,24,24,48,24,48,48,96,12,24,24,48,24,48,48,96,24,...
(End)
		

Crossrefs

Cf. A001316.

Programs

  • Maple
    read("transforms3") ; L := BFILETOLIST("b001316.txt") ; for n from 1 to 120 do printf("%d,",3*op(n,L)) ; od: # R. J. Mathar, Jul 13 2009

Extensions

More terms from R. J. Mathar, Jul 13 2009

A165641 A091137(n) / A001316(n) .

Original entry on oeis.org

1, 1, 6, 6, 360, 360, 15120, 15120, 1814400, 1814400, 119750400, 119750400, 653837184000, 653837184000, 3923023104000, 3923023104000, 16005934264320000, 16005934264320000, 12772735542927360000, 12772735542927360000, 8430005458332057600000, 8430005458332057600000
Offset: 0

Views

Author

Paul Curtz, Sep 23 2009

Keywords

Crossrefs

Extensions

Edited and extended by R. J. Mathar, Sep 25 2009

A268433 a(n) = A106184(n) / A001316(n).

Original entry on oeis.org

1, 1, 5, 7, 59, 95, 377, 655, 10163, 18459, 71099, 132641, 1021455, 1937515, 7477505, 14335423, 443971523, 857241875, 3328921191, 6459762413, 50311588373, 97986366561, 382518036575, 747066030569, 11690129046071, 22881444619663, 89673873841559, 175837008468485
Offset: 0

Views

Author

Peter Luschny, Feb 24 2016

Keywords

Crossrefs

Programs

  • Maple
    H := n -> hypergeom([1/2,-n/2,-n/2+1/2],[-n/2+3/4,-n/2+1/4],1/2):
    A000984 := n -> 4^n*hypergeom([-n,1/2],[1],1):
    A001316 := n -> 2^(add(i, i = convert(n, base, 2))):
    a := n -> H(n)*A000984(n)/A001316(n): seq(simplify(a(n)),n=0..27);

Formula

a(n) = 2^(2*n-A000120(n))*hypergeometric([-n,1/2],[1],1)*hypergeometric([1/2,-n/2,-n/2+1/2],[-n/2+3/4,-n/2+1/4],1/2).

A102377 Gould's sequence A001316 in binary.

Original entry on oeis.org

1, 10, 10, 100, 10, 100, 100, 1000, 10, 100, 100, 1000, 100, 1000, 1000, 10000, 10, 100, 100, 1000, 100, 1000, 1000, 10000, 100, 1000, 1000, 10000, 1000, 10000, 10000, 100000, 10, 100, 100, 1000, 100, 1000, 1000, 10000, 100, 1000, 1000, 10000, 1000
Offset: 0

Views

Author

Paul Barry, Jan 05 2005

Keywords

Crossrefs

Programs

  • PARI
    a(n) = 10^hammingweight(n); \\ Kevin Ryde, Jan 11 2024

Formula

Formulas due to Paul D. Hanna:
a(n) = 10^A000120(n).
a(n) = Product_{k=0..log_2(n)} 10^b(n,k) where b(n,k) = coefficient of 2^k in binary expansion of n.
a(n) = Sum_{k=0..n} (C(n,k) mod 2)*9^A000120(n-k).
G.f.: Product_{k>=0} 1 + 10*x^(2^k).
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