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.

A096782 A096780(A096780(n)).

Original entry on oeis.org

1, 2, 3, 4, 56, 11, 57, 22, 5, 8, 28, 7, 3082, 254, 79, 6, 9317, 9, 907, 12, 17, 174, 8003, 137, 23, 33, 667, 14, 677, 13
Offset: 1

Views

Author

Reinhard Zumkeller, Jul 09 2004

Keywords

Comments

Integer permutation with inverse A096781: a(A096781(n))=A096781(a(n))=n;
A075383(a(n))=a(A075383(n))=A096780(n).

Links

A075383 Rearrangement of natural numbers so that next n numbers are each divisible by n.

Original entry on oeis.org

1, 2, 4, 3, 6, 9, 8, 12, 16, 20, 5, 10, 15, 25, 30, 18, 24, 36, 42, 48, 54, 7, 14, 21, 28, 35, 49, 56, 32, 40, 64, 72, 80, 88, 96, 104, 27, 45, 63, 81, 90, 99, 108, 117, 126, 50, 60, 70, 100, 110, 120, 130, 140, 150, 160, 11, 22, 33, 44, 55, 66, 77, 121, 132, 143, 154, 84
Offset: 1

Views

Author

Amarnath Murthy, Sep 22 2002

Keywords

Comments

Integer permutation with inverse A096780: a(A096780(n))=A096780(a(n))=n; A096781(n) = a(a(n)). - Reinhard Zumkeller, Jul 09 2004
Primes occur in natural order: a(A072205(n)) = A000040(n). - Reinhard Zumkeller, Jun 22 2009
n = greatest common divisor of row n. - Reinhard Zumkeller, Nov 30 2015

Examples

			   1;
   2,  4;
   3,  6,  9;
   8, 12, 16, 20;
   5, 10, 15, 25, 30;
  18, 24, 36, 42, 48, 54;
   7, 14, 21, 28, 35, 49, 56;
  32, ...

Links

Crossrefs

Cf. A075384, A075385, A075386, A075387, A075388, A075389, A075390.
Cf. A000040, A072205, A096780, A096781, A263896 (central terms).

Programs

  • Haskell
    import Data.List ((\\))
a075383 n k = a075383_tabl !! (n-1) !! (k-1)
a075383_row n = a075383_tabl !! (n-1)
a075383_tabl = f 1 [1..] where
   f x zs = ys : f (x + 1) (zs \\ ys) where
            ys = take x $ filter ((== 0) . (`mod` x)) zs
a075383_list = concat a075383_tabl
-- Reinhard Zumkeller, Nov 30 2015
  • Mathematica
    row[1] = {1}; row[n_] := row[n] = (For[rows = Join[row /@ Range[n-1]]; ro = {}; k = n, Length[ro] < n, k = k+n, If[FreeQ[rows, k], AppendTo[ro, k]]]; ro); Array[row, 12] // Flatten (* Jean-François Alcover, Apr 28 2017 *)

Extensions

More terms from Sascha Kurz, Jan 28 2003

A096781 a(n) = A075383(A075383(n)).

Original entry on oeis.org

1, 2, 3, 4, 9, 16, 12, 10, 18, 48, 6, 20, 30, 28, 40, 36, 21, 104, 99, 70, 150, 8, 25, 54, 56, 96, 100, 11, 72, 81, 132, 192, 26, 195, 224, 350, 49, 126, 121, 39, 221, 280, 135, 345, 304, 110, 55, 168, 294, 225, 390, 384, 68, 323, 414, 5, 7, 80, 117, 160, 154, 252
Offset: 1

Views

Author

Reinhard Zumkeller, Jul 09 2004

Keywords

Comments

Integer permutation with inverse A096782: a(A096782(n)) = A096782(a(n)) = n;
A096780(a(n)) = a(A096780(n)) = A075383(n).

Links

Crossrefs

Cf. A075383.

Programs

  • Haskell
    a096781 = a . a where a = (a075383_list !!) . subtract 1
-- Reinhard Zumkeller, Nov 29 2015
Showing 1-3 of 3 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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