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.

A195035 Multiples of 15 and of 8 interleaved: a(2n-1) = 15n, a(2n) = 8n.

Original entry on oeis.org

15, 8, 30, 16, 45, 24, 60, 32, 75, 40, 90, 48, 105, 56, 120, 64, 135, 72, 150, 80, 165, 88, 180, 96, 195, 104, 210, 112, 225, 120, 240, 128, 255, 136, 270, 144, 285, 152, 300, 160, 315, 168, 330, 176, 345, 184, 360, 192, 375, 200, 390, 208, 405, 216
Offset: 1

Views

Author

Omar E. Pol, Sep 12 2011

Keywords

Comments

First differences of A195036.
a(n) is also the length of the n-th edge of a square spiral in which the first two edges are the legs of the primitive Pythagorean triple [15, 8, 17]. Zero together with partial sums give A195036; the vertices of the spiral.

Crossrefs

Programs

Formula

From Bruno Berselli, Sep 30 2011: (Start)
G.f.: x*(15+8*x)/((1-x)^2*(1+x)^2).
a(n) = A010686(n)*A010706(n-1)*A004526(n+1) = (23*n-(7*n+15)*(-1)^n+15)/4.
a(n) = 2*a(n-2) - a(n-4).
a(-n) = -a(A014681(n-1)). (End)

A243520 Numbers that are congruent to {0, 8} mod 11.

Original entry on oeis.org

0, 8, 11, 19, 22, 30, 33, 41, 44, 52, 55, 63, 66, 74, 77, 85, 88, 96, 99, 107, 110, 118, 121, 129, 132, 140, 143, 151, 154, 162, 165, 173, 176, 184, 187, 195, 198, 206, 209, 217, 220, 228, 231, 239, 242, 250, 253, 261, 264, 272, 275, 283, 286, 294, 297, 305
Offset: 0

Views

Author

Viet Quoc Le Tran, Jun 14 2014

Keywords

Comments

Union of A008593 and A017485. - Michel Marcus, Jun 15 2014
This sequence mimics in some sense the ceiling function of n/2 (the seq. A110654) relative to variations from a main class of recurrence relations; in order to get the ceiling function of n/2 (see Formula section), the vector v must be [0,1] instead of [3,8]. - R. J. Cano, Jun 15 2014

Crossrefs

Programs

  • Magma
    &cat [[11*n,11*n+8]: n in [0..30]]; // [Bruno Berselli, Jun 16 2014]
  • Maple
    A243520:=n->5*n + 2*(n mod 2) + ceil(n/2); seq(A243520(n), n=0..50); # Wesley Ivan Hurt, Jun 21 2014
  • Mathematica
    Flatten[Table[11 n + {0, 8}, {n, 0, 32}]] (* Alonso del Arte, Jun 15 2014 *)
  • PARI
    a(n)=5*n+2*(n%2)+ceil(n/2); \\ R. J. Cano, Jun 15 2014
    
  • PARI
    a(n)=if(!n,0,a(n-1)+[3,8][1+n%2]); \\ R. J. Cano, Jun 15 2014
    

Formula

a(n) = -5/4*(-1)^n + 11*n/2 + 5/4.
From R. J. Cano, Jun 15 2014: (Start)
a(n) = 5*n + 2*(n mod 2) + ceiling(n/2).
If n=0 then a(n) is zero, else a(n) = a(n-1) + v[n mod 2], where v is [3,8]. (End)
G.f.: x*(8 + 3*x) / ((1 + x)*(1 - x)^2). [Bruno Berselli, Jun 16 2014]
a(n) = sum( A010706(i), i=0..n ) - 3. [Bruno Berselli, Jun 16 2014]
E.g.f.: (11*x*exp(x) + 5*sinh(x))/2. - David Lovler, Sep 04 2022

A176107 Decimal expansion of (6+sqrt(42))/4.

Original entry on oeis.org

3, 1, 2, 0, 1, 8, 5, 1, 7, 4, 6, 0, 1, 9, 6, 5, 0, 5, 7, 7, 4, 1, 4, 9, 1, 8, 5, 9, 0, 2, 1, 9, 9, 9, 1, 6, 4, 4, 2, 6, 3, 0, 1, 0, 7, 6, 7, 6, 4, 5, 8, 6, 6, 3, 7, 4, 2, 7, 8, 3, 8, 5, 9, 9, 4, 5, 2, 4, 0, 4, 3, 4, 4, 4, 6, 1, 0, 1, 1, 0, 9, 2, 8, 5, 0, 0, 9, 0, 2, 2, 6, 6, 5, 1, 4, 0, 2, 5, 5, 8, 9, 1, 8, 8, 6
Offset: 1

Views

Author

Klaus Brockhaus, Apr 10 2010

Keywords

Comments

Continued fraction expansion of (6+sqrt(42))/4 is A010706.

Examples

			(6+sqrt(42))/4 = 3.12018517460196505774...
		

Crossrefs

Cf. A010496 (decimal expansion of sqrt(42)), A010706 (repeat 3, 8).

Programs

  • Mathematica
    RealDigits[(6+Sqrt[42])/4,10,120][[1]] (* Harvey P. Dale, Jun 22 2012 *)

A176454 Decimal expansion of (12+2*sqrt(42))/3.

Original entry on oeis.org

8, 3, 2, 0, 4, 9, 3, 7, 9, 8, 9, 3, 8, 5, 7, 3, 4, 8, 7, 3, 1, 0, 6, 4, 4, 9, 5, 7, 3, 9, 1, 9, 9, 7, 7, 7, 1, 8, 0, 3, 4, 6, 9, 5, 3, 8, 0, 3, 8, 8, 9, 7, 6, 9, 9, 8, 0, 7, 5, 6, 9, 5, 9, 8, 5, 3, 9, 7, 4, 4, 9, 1, 8, 5, 6, 2, 6, 9, 6, 2, 4, 7, 6, 0, 0, 2, 4, 0, 6, 0, 4, 4, 0, 3, 7, 4, 0, 1, 5, 7, 1, 1, 6, 9, 6
Offset: 1

Views

Author

Klaus Brockhaus, Apr 20 2010

Keywords

Comments

Continued fraction expansion of (12+2*sqrt(42))/3 is A010706 preceded by 8.

Examples

			(12+2*sqrt(42))/3 = 8.32049379893857348731...
		

Crossrefs

Cf. A010496 (decimal expansion of sqrt(42)), A010706 (repeat 3, 8).

Programs

  • Mathematica
    RealDigits[(12+2*Sqrt[42])/3,10,120][[1]] (* Harvey P. Dale, Nov 23 2016 *)
Showing 1-4 of 4 results.