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 1-2 of 2 results.

A090730 a(n) = 22*a(n-1) - a(n-2), starting with a(0) = 2 and a(1) = 22.

Original entry on oeis.org

2, 22, 482, 10582, 232322, 5100502, 111978722, 2458431382, 53973511682, 1184958825622, 26015120652002, 571147695518422, 12539234180753282, 275292004281053782, 6043884860002429922, 132690174915772404502
Offset: 0

Views

Author

Nikolay V. Kosinov (kosinov(AT)unitron.com.ua), Jan 18 2004

Keywords

Crossrefs

Programs

  • Mathematica
    a[0] = 2; a[1] = 22; a[n_] := 22a[n - 1] - a[n - 2]; Table[ a[n], {n, 0, 15}] (* Robert G. Wilson v, Jan 30 2004 *)
    LinearRecurrence[{22,-1},{2,22},20] (* Harvey P. Dale, Mar 07 2018 *)
  • Sage
    [lucas_number2(n,22,1) for n in range(0,20)] # Zerinvary Lajos, Jun 26 2008

Formula

a(n) = p^n + q^n, where p = 11 + 2*sqrt(30) and q = 11 - 2*sqrt(30). - Tanya Khovanova, Feb 06 2007
G.f.: (2-22*x)/(1-22*x+x^2). - Philippe Deléham, Nov 18 2008
a(n) = 2*A077422(n). - R. J. Mathar, Sep 27 2014

A351744 Increment all even digits of n.

Original entry on oeis.org

1, 1, 3, 3, 5, 5, 7, 7, 9, 9, 11, 11, 13, 13, 15, 15, 17, 17, 19, 19, 31, 31, 33, 33, 35, 35, 37, 37, 39, 39, 31, 31, 33, 33, 35, 35, 37, 37, 39, 39, 51, 51, 53, 53, 55, 55, 57, 57, 59, 59, 51, 51, 53, 53, 55, 55, 57, 57, 59, 59, 71, 71, 73, 73, 75, 75, 77, 77
Offset: 0

Views

Author

Alex Ratushnyak, Feb 17 2022

Keywords

Crossrefs

Programs

  • Mathematica
    Array[FromDigits@ Map[If[EvenQ[#], # + 1, #] &, IntegerDigits[#]] &, 78, 0] (* Michael De Vlieger, Feb 17 2022 *)
  • PARI
    a(n) = if (n, fromdigits(apply(x->if(!(x%2),x+1,x), digits(n))), 1); \\ Michel Marcus, Feb 18 2022
  • Python
    for n in range(1000):
      s = str(n)
      res = ''
      for d in s:
        if (int(d) & 1)==0:  d = str(int(d)+1)
        res += d
      print(int(res), end=',')
    
  • Python
    def A351744(n): return int(str(n).translate({48:49,50:51,52:53,54:55,56:57})) # Chai Wah Wu, Apr 07 2022
    
Showing 1-2 of 2 results.