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.

A086848 First differences are formed by interleaving {2^k - 1, k = 1, 2, 3, ...} and {11*k, k = 5, 4, 3, ...}.

Original entry on oeis.org

42, 43, 98, 101, 145, 152, 185, 200, 222, 253, 264, 327, 327, 454, 443, 698, 676, 1187, 1154, 2177, 2133, 4180, 4125, 8220, 8154, 16345, 16268, 32651, 32563, 65330, 65231, 130766, 130656, 261727, 261606, 523749, 523617, 1047904
Offset: 1

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Author

Michael M. Taylor, Aug 09 2003

Keywords

Comments

A version of this was given as a puzzle somewhere.
There are infinitely many solutions to the stated sequence name producing the specified interleaving as a first difference. I assume there was some other condition given in the puzzle that arrived at this particular solution. - Ray Chandler, May 07 2025

Crossrefs

Formula

Empirical g.f.: x*(48*x^6+34*x^4-x^3-113*x^2+x+42) / ((x-1)^3*(x+1)^2*(2*x^2-1)). - Colin Barker, Mar 05 2013
Conjectured g.f. above confirmed. Interleaving of two linear recurrences is another linear recurrence, as is the first difference. - Ray Chandler, May 07 2025

A087099 Partial sums of A063914.

Original entry on oeis.org

1, 3, 6, 11, 16, 24, 31, 42, 51, 65, 76, 93, 106, 126, 141, 164, 181, 207, 226, 255, 276, 308, 331, 366, 391, 429, 456, 497, 526, 570, 601, 648, 681, 731, 766, 819, 856, 912, 951, 1010, 1051, 1113, 1156, 1221, 1266, 1334, 1381, 1452, 1501, 1575, 1626
Offset: 1

Views

Author

Jeremy Gardiner, Aug 10 2003

Keywords

Crossrefs

Programs

  • Mathematica
    With[{nn=50},Accumulate[Riffle[Range[1,2*nn,2],3*Range[0,nn]+2]]] (* Harvey P. Dale, Jul 25 2013 *)

Formula

From Chai Wah Wu, Feb 02 2021: (Start)
a(n) = 2*a(n-2) - a(n-4) for n > 4.
G.f.: x*(x^3 + x^2 + 2*x + 1)/((x - 1)^2*(x + 1)^2). (End)

A087100 A000225 (2^n - 1) interlaced with A008593 (11n).

Original entry on oeis.org

0, 1, 11, 3, 22, 7, 33, 15, 44, 31, 55, 63, 66, 127, 77, 255, 88, 511, 99, 1023, 110, 2047, 121, 4095, 132, 8191, 143, 16383, 154, 32767, 165, 65535, 176, 131071, 187, 262143, 198, 524287, 209, 1048575, 220, 2097151, 231, 4194303, 242, 8388607, 253
Offset: 0

Views

Author

Jeremy Gardiner, Aug 10 2003

Keywords

Crossrefs

Programs

  • Mathematica
    Rest[With[{nn=30},Riffle[2^Range[0,nn]-1,11Range[0,nn]]]] (* Harvey P. Dale, Aug 15 2011 *)

Formula

From Chai Wah Wu, Feb 02 2021: (Start)
a(n) = 4*a(n-2) - 5*a(n-4) + 2*a(n-6) for n > 5.
G.f.: x*(22*x^3 + x^2 - 11*x - 1)/((x - 1)^2*(x + 1)^2*(2*x^2 - 1)). (End)
Showing 1-3 of 3 results.