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.

A065259 A057114 conjugated with A059893, inverse of A065260.

Original entry on oeis.org

3, 1, 7, 2, 11, 5, 15, 4, 19, 9, 23, 6, 27, 13, 31, 8, 35, 17, 39, 10, 43, 21, 47, 12, 51, 25, 55, 14, 59, 29, 63, 16, 67, 33, 71, 18, 75, 37, 79, 20, 83, 41, 87, 22, 91, 45, 95, 24, 99, 49, 103, 26, 107, 53, 111, 28, 115, 57, 119, 30, 123, 61, 127, 32, 131, 65, 135, 34, 139
Offset: 1

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Author

Antti Karttunen, Oct 28 2001

Keywords

Examples

			G.f. = 3*x + x^2 + 7*x^3 + 2*x^4 + 11*x^5 + 5*x^6 + 15*x^7 + 4*x^8 + ...
		

Programs

  • PARI
    Vec(x*(3+x+7*x^2+2*x^3+5*x^4+3*x^5+x^6)/((1-x)^2*(1+x)^2*(1+x^2)^2) + O(x^100)) \\ Colin Barker, Oct 29 2016
    
  • PARI
    {a(n) = if( n%2, 2*n+1, n%4, n-1, n/2)}; /* Michael Somos, Nov 06 2016 */

Formula

a(n) = A059893(A057114(A059893(n))).
a(2*k+1) = 4*k+3, a(4*k+2) = 4*k+1, a(4*k+4) = 2*k+2. - Ralf Stephan, Jun 10 2005
a(n) = (11*n+2-(5*n+6)*(-1)^n+(n-2)*(1+(-1)^n)*(-1)^((2*n-3-(-1)^n)/4))/8. - Luce ETIENNE, Oct 29 2016
From Colin Barker, Oct 29 2016: (Start)
a(n) = 2*a(n-4) - a(n-8) for n>8.
G.f.: x*(3 + x + 7*x^2 + 2*x^3 + 5*x^4 + 3*x^5 + x^6)/((1 - x)^2*(1 + x)^2*(1 + x^2)^2). (End)