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 1-4 of 4 results.

A161341 First differences of A161340.

Original entry on oeis.org

1, 26, 56, 260, 56, 392, 392, 2192, 56, 392, 392, 2744, 392, 2744, 2744, 16952, 56, 392, 392, 2744, 392, 2744, 2744, 19208, 392, 2744, 2744, 19208, 2744, 19208, 19208, 125336, 56, 392, 392, 2744, 392, 2744, 2744, 19208, 392, 2744, 2744, 19208, 2744, 19208, 19208
Offset: 1

Views

Author

Omar E. Pol, Jun 14 2009

Keywords

Examples

			From _Omar E. Pol_, Mar 15 2020: (Start)
Written as an irregular triangle in which row lengths give A011782 the sequence begins:
1;
26;
56, 260;
56, 392, 392, 2192;
56, 392, 392, 2744, 392, 2744, 2744, 16952;
56, 392, 392, 2744, 392, 2744, 2744, 19208, 392, 2744, 2744, 19208, 2744, ...
(End)
		

Crossrefs

Programs

  • PARI
    f(n) = 8*7^hammingweight(n-1); \\ A160429
    ispow2(n) = my(k); (n==2) || (ispower(n,,&k) && (k==2));
    a(n) = if (n==1, 1, if (ispow2(n), f(n) - 3*n*(3*n - 1), f(n))); \\ Michel Marcus, Mar 15 2020

Formula

a(n) = A160429(n) for n>1 and n not a power of 2.
a(n) = A160429(n) - 3n*(3n - 1) for n>1 and n a power of 2.

Extensions

Formula and more terms from Nathaniel Johnston, Nov 15 2010
More terms from Jinyuan Wang, Mar 14 2020

A160428 Number of ON cells at n-th stage of three-dimensional version of the cellular automaton A160410, using cubes.

Original entry on oeis.org

0, 8, 64, 120, 512, 568, 960, 1352, 4096, 4152, 4544, 4936, 7680, 8072, 10816, 13560, 32768, 32824, 33216, 33608, 36352, 36744, 39488, 42232, 61440, 61832, 64576, 67320, 86528, 89272, 108480, 127688, 262144, 262200, 262592, 262984, 265728, 266120, 268864, 271608
Offset: 0

Views

Author

Omar E. Pol, Jun 01 2009

Keywords

Crossrefs

Programs

  • Mathematica
    a[n_] := 8*Sum[7^DigitCount[k, 2, 1], {k, 0, n - 1}]; Array[a, 40, 0] (* Michael De Vlieger, Nov 01 2022 *)

Formula

a(n) = 8 * Sum_{k=0..n-1} 7^A000120(k)
a(n) = 8 + 56 * Sum_{k=1..n-1} A151785(k) for n >= 1

Extensions

Formulas and more terms from Nathaniel Johnston, Nov 13 2010
More terms from Michael De Vlieger, Nov 01 2022

A163989 First differences of A160379.

Original entry on oeis.org

1, 26, 8, 200, 26, 620, 56, 1304, 98, 2252, 152, 3464, 218, 4940, 296, 6680, 386, 8684, 488, 10952, 602, 13484, 728, 16280, 866, 19340, 1016, 22664, 1178, 26252, 1352, 30104, 1538, 34220, 1736, 38600, 1946, 43244, 2168, 48152, 2402, 53324, 2648, 58760, 2906
Offset: 1

Views

Author

Omar E. Pol, Sep 20 2009

Keywords

Crossrefs

Programs

  • Mathematica
    LinearRecurrence[{0,3,0,-3,0,1},{1,26,8,200,26,620,56,1304},50] (* Harvey P. Dale, May 19 2025 *)
  • PARI
    Vec(-x*(18*x^3+x^2+26*x+1)*(x^4+4*x^2+1)/((x-1)^3*(x+1)^3)  + O(x^100)) \\ Colin Barker, Sep 17 2013

Formula

a(2n+1) = 6n^2 + 2 for n>=1.
a(2n) = 132n^2 - 240n + 152 for n>=2.
From Colin Barker, Sep 17 2013: (Start)
a(n) = 3*a(n-2)-3*a(n-4)+a(n-6) for n>8.
G.f.: -x*(18*x^3+x^2+26*x+1)*(x^4+4*x^2+1) / ((x-1)^3*(x+1)^3). (End)

Extensions

Formula and more terms from Nathaniel Johnston, Nov 15 2010
More terms from Colin Barker, Sep 17 2013

A163987 First differences of A160119.

Original entry on oeis.org

1, 26, 8, 200, 8, 200, 56, 1400, 8, 200, 56, 1400, 56, 1400, 392, 9800, 8, 200, 56, 1400, 56, 1400, 392, 9800, 56, 1400, 392, 9800, 392, 9800, 2744, 68600
Offset: 1

Views

Author

Omar E. Pol, Sep 20 2009

Keywords

Crossrefs

Formula

a(2n-1) = 8*A151785(n-1), n >= 2, a(2n) = 200*A151785(n-1), n >= 2. - Nathaniel Johnston, Mar 24 2011

Extensions

a(8)-a(32) from Nathaniel Johnston, Mar 24 2011
Showing 1-4 of 4 results.