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.

A064550 a(1) = 2, a(n)=a(n-1)+2*Q(n)-n, n > 1 where Q = A005185.

Original entry on oeis.org

1, 2, 4, 7, 9, 12, 16, 19, 23, 26, 28, 33, 37, 40, 46, 49, 53, 58, 62, 67, 71, 74, 76, 85, 89, 92, 98, 103, 107, 110, 120, 123, 125, 132, 140, 143, 147, 154, 158, 163, 169, 174, 180, 185, 189, 192, 194, 211, 211, 212, 222, 227, 227, 234, 240, 241
Offset: 0

Views

Author

Roger L. Bagula, Oct 08 2001

Keywords

Crossrefs

Programs

  • ARIBAS
    function a064550(maxarg: integer); var n,r,rm,q: integer; qar: array; begin qar := alloc(array,maxarg + 1); qar[0] := 1; for n := 1 to maxarg do if n < 2 then q := 1; else q := qar[n - qar[n - 1]] + qar[n - qar[n - 2]]; end; qar[n] := q; if n = 1 then r := 2; else r := rm + round(2*(q - n/2)); end; rm := r; write(r," "); end; end; a064550(65);
    
  • Haskell
    a064550 n = a064550_list !! n
    a064550_list = 1 : 2 : zipWith3 (\a q n -> a + 2 * q - n)
        (tail a064550_list) (drop 2 a005185_list) [2..]
    -- Reinhard Zumkeller, May 13 2012
  • Maple
    A064550 := proc(n) option remember; if n=0 then 1 else A064550(n-1)+2*A005185(n-1)(n) - n; fi; end;
  • Mathematica
    q[0] = q[1] = 1;
    q[n_] := q[n - q[n - 1]] + q[n - q[n - 2]];
    a[1] = 2;
    a[n_] := a[n] = a[n - 1] + 2*(q[n] - n/2);
    Table[ a[n], {n, 1, 70} ]

Extensions

More terms from Vladeta Jovovic, Klaus Brockhaus and Matthew Conroy, Oct 09 2001

A064551 Ado [Simone Caramel]'s function: a(0) = 1, a(n) = a(n-1) + 2*(Fibonacci(n+1)-n), n > 0.

Original entry on oeis.org

1, 1, 1, 1, 3, 9, 23, 51, 103, 195, 353, 619, 1061, 1789, 2981, 4925, 8087, 13221, 21547, 35039, 56891, 92271, 149541, 242231, 392233, 634969, 1027753, 1663321, 2691723, 4355745, 7048223, 11404779, 18453871, 29859579, 48314441, 78175075, 126490637, 204666901, 331158797
Offset: 0

Views

Author

Roger L. Bagula, Oct 08 2001

Keywords

Comments

A Pickover sequence with properties analogous to the primes.

References

  • Ado [Simone Caramel], Postings in egroups and newsgroups.

Crossrefs

Programs

  • ARIBAS
    function a064551(maxarg: integer); var n,r,rm,q,qm1,qm2: integer; begin qm2 := 0; qm1 := 0; rm := 0; for n := 0 to maxarg do if n < 2 then q := 1; else q := qm1 + qm2; end; qm2 := qm1; qm1 := q; if n = 0 then r := 1; else r := rm + 2*(q - n); end; rm := r; write(r," "); end; end; a064551(35);
    
  • Haskell
    a064551 n = a064551_list !! n
    a064551_list = 1 : zipWith (+) a064551_list
                       (map (* 2) $ zipWith (-) (drop 2 a000045_list) [1..])
    -- Reinhard Zumkeller, Sep 13 2013
  • Maple
    a:= proc(n) option remember: a(n-1)+2*(combinat[fibonacci](n+1)-n) end: a(0):=1: for n from 0 to 60 do printf(`%d, `, a(n)) od:
  • Mathematica
    a[0] = f[0] = f[1] = 1; f[n_] := f[n] = f[n - 1] + f[n - 2]; a[n_] := a[n] = a[n - 1] + 2*(f[n] - n); Table[ a[n], {n, 0, 40} ]
    LinearRecurrence[{4,-5,1,2,-1},{1,1,1,1,3},50] (* Harvey P. Dale, Sep 27 2011 *)

Formula

From T. D. Noe, Oct 12 2007: (Start)
G.f.: (1 - 3x + 2x^2 + x^3 + x^4)/((x-1)^3 (x^2 + x - 1)).
a(n) = 4*a(n-1) - 5*a(n-2) + a(n-3) + 2*a(n-4) - a(n-5). (End)
a(n) = (1/5)*2^(-n)*(-15*2^n + (10-4*sqrt(5))*(1-sqrt(5))^n + (1+sqrt(5))^n*(10+4*sqrt(5))) - n - n^2. - Jean-François Alcover, May 28 2013
a(n) = a(n-1) - 2 * A065220(n), n > 0. - Reinhard Zumkeller, Sep 13 2013
a(n) = 2*F(n+3) - n^2 - n - 3 = 1 + 2*Sum_{k=1..n} F(k+1) - k = 1 + 2*Sum_{k=1..n} A001924(k-3), F=A000045. - Ehren Metcalfe, Dec 27 2018
E.g.f.: 4*exp(x/2)*(5*cosh(sqrt(5)*x/2) + 2*sqrt(5)*sinh(sqrt(5)*x/2))/5 - exp(x)*(3 + x*(2 + x)). - Stefano Spezia, Oct 16 2023

A064714 Define q(0)=1, q(1)=1, q(2)=1, q(n)=q(abs(n-q(n-2)))+q(abs(n-q(n-3))) (A063892); then a(0) = 1, a(n)=a(n-1)+2*(q(n)-n/2), n > 0.

Original entry on oeis.org

1, 2, 2, 3, 7, 14, 18, 17, 15, 24, 26, 23, 25, 36, 40, 35, 33, 36, 50, 63, 63, 66, 68, 77, 81, 98, 98, 105, 93, 92, 110, 131, 137, 128, 110, 121, 129, 138, 124, 119, 115, 130, 158, 167, 155, 154, 176, 223, 219, 182, 152, 173, 259, 278, 266, 261, 271, 296, 304, 303
Offset: 0

Views

Author

Robert G. Wilson v, Oct 13 2001

Keywords

Crossrefs

Programs

  • Mathematica
    a[0] = q[0] = q[1] = q[2] = 1; q[n_] := q[n] = q[Abs[n - q[n - 2]]] + q[Abs[n - q[n - 3]]]; a[n_] := a[n] = a[n - 1] + 2*(q[n] - n/2); Table[a[n], {n, 0, 70} ]
Showing 1-3 of 3 results.