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.

A082205 Palindromes pertaining to A082204.

Original entry on oeis.org

1, 22, 232, 3223, 22322, 232232, 3223223, 22322322, 232232232, 3223223223, 22322322322, 232232232232, 3223223223223, 22322322322322, 232232232232232, 3223223223223223, 22322322322322322, 232232232232232232, 3223223223223223223
Offset: 1

Views

Author

Amarnath Murthy, Apr 10 2003

Keywords

Comments

Perhaps no digits other than 1,2 and 3 occur. From the second term onwards the periodic pattern of two 2's followed by a 3 holds.

Examples

			The first six palindromes are:  1, 22, 232, 3223,22322, 232232.
		

Crossrefs

Programs

  • Mathematica
    Join[{1},LinearRecurrence[{0, 0, 1001, 0, 0, -1000},{22, 232, 3223, 22322, 232232, 3223223},18]] (* Ray Chandler, Aug 25 2015 *)

Extensions

More terms from Joshua Zucker, May 08 2006

A082206 Digit sum of A082205(n).

Original entry on oeis.org

1, 4, 7, 10, 11, 14, 17, 18, 21, 24, 25, 28, 31, 32, 35, 38, 39, 42, 45, 46, 49, 52, 53, 56, 59, 60, 63, 66, 67, 70, 73, 74, 77, 80, 81, 84, 87, 88, 91, 94, 95, 98, 101, 102, 105, 108, 109, 112, 115, 116, 119, 122, 123, 126, 129, 130, 133, 136, 137, 140, 143, 144
Offset: 1

Views

Author

Amarnath Murthy, Apr 10 2003

Keywords

Examples

			The first six palindromes are 1, 22, 232, 3223, 22322, 232232.
		

Crossrefs

Essentially the same as A047342.

Programs

  • Magma
    R:=PowerSeriesRing(Integers(), 70); Coefficients(R!( (1+3*x+3*x^2+2*x^3-2*x^4)/((1-x)*(1-x^3)) )); // G. C. Greubel, Jan 22 2024
    
  • Mathematica
    CoefficientList[Series[(1+3x+3x^2+2x^3-2x^4)/((1-x)*(1-x^3)),{x,0,70}],x] (* Vladimir Joseph Stephan Orlovsky, Jan 26 2012 *)
    Join[{1},LinearRecurrence[{1, 0, 1, -1},{4, 7, 10, 11},61]] (* Ray Chandler, Aug 25 2015 *)
  • SageMath
    def a(n): # a = A082206
        if n<5: return 3*n-2
        else: return a(n-3) + 7
    [a(n) for n in range(1,71)] # G. C. Greubel, Jan 22 2024

Formula

For n>1, a(n+3) = a(n) + 7.
a(n) = A007953(A082205(n)).
G.f.: x*(1 + 3*x + 3*x^2 + 2*x^3 - 2*x^4)/((1-x)*(1-x^3)). - Vladimir Joseph Stephan Orlovsky, Jan 26 2012
a(n) = -a(n-1) - a(n-2) + 7*(n-1), for n >= 4, with a(n) = 3*n-2 for n < 4. - G. C. Greubel, Jan 22 2024

Extensions

Edited by Don Reble, Mar 13 2006
Offset corrected by Mohammed Yaseen, Aug 15 2023
Showing 1-2 of 2 results.