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 1-10 of 18 results. Next

A075384 Initial term of n-th group in A075383.

Original entry on oeis.org

1, 2, 3, 8, 5, 18, 7, 32, 27, 50, 11, 84, 13, 98, 75, 128, 17, 162, 19, 200, 147, 242, 23, 312, 125, 338, 243, 392, 29, 510, 31, 512, 363, 578, 245, 684, 37, 722, 507, 920, 41, 882, 43, 968, 765, 1058, 47, 1392, 343, 1250, 867, 1352, 53, 1458, 605, 1624, 1083, 1682, 59, 2220, 61, 1922, 1449, 2368, 845
Offset: 1

Views

Author

Amarnath Murthy, Sep 22 2002

Keywords

Links

Crossrefs

Cf. A075383, A075385, A075386, A075387, A075388.

Programs

  • Haskell
    a075384 = head . a075383_row  -- Reinhard Zumkeller, Nov 29 2015
  • Maple
    A075383 := proc(nmax) local a,n,ct,k; a := [1,2,4] ; for n from 3 do ct := 0 ; for k from 1 do if (k*n) in a then ; else a := [op(a),k*n] ; ct := ct+1 ; if ct >= n then break ; fi ; fi; od: if nops(a) > nmax then RETURN(a) ; fi; od: end: A075384 := proc(n,a075383) local i,k ; i := 1 ; for k from 1 to n-1 do i := i+k ; if i > nops(a075383) then RETURN(-1) ; fi; od: RETURN(op(i,a075383)) ; end: a075383 := A075383(4000) : for n from 1 to 70 do a084 := A075384(n,a075383) ; if a084 < 0 then break; else printf("%d,",a084) ; fi; od:
  • Mathematica
    row[n_] := row[n] = If[n == 1, {1}, rows = Join[row /@ Range[n-1]]; ro = {}; For[k = n, Length[ro] < n, k = k + n, If[FreeQ[rows, k], AppendTo[ro, k]]]; ro]; a[n_] := row[n][[1]]; Array[a, 65] (* Jean-François Alcover, Jan 27 2018 *)

Extensions

More terms from Reinhard Zumkeller, Jul 09 2004
Removed claim on relation to A096776. Corrected from a(20) on by R. J. Mathar, Oct 31 2008

A075386 Sum of terms of n-th group in A075383.

Original entry on oeis.org

1, 6, 18, 56, 85, 222, 210, 576, 756, 1090, 858, 2328, 1573, 3598, 3930, 5488, 3111, 8154, 4427, 11060, 11676, 15004, 8073, 21336, 18125, 24726, 24516, 32060, 16530, 43410, 20243, 48576, 46101, 56780, 55685, 75780, 36186, 83106, 82524, 109480
Offset: 1

Views

Author

Amarnath Murthy, Sep 22 2002

Keywords

Links

Crossrefs

Cf. A075383, A075384, A075385, A075387, A075390.

Programs

Extensions

More terms from David Wasserman, Jan 17 2005

A075385 Final term of n-th group in A075383.

Original entry on oeis.org

1, 4, 9, 20, 30, 54, 56, 104, 126, 160, 154, 264, 234, 364, 390, 480, 374, 630, 475, 780, 819, 946, 713, 1200, 1100, 1326, 1350, 1596, 1160, 1950, 1333, 2144, 2046, 2312, 2380, 2844, 1961, 3002, 3081, 3600, 2378, 3948, 2666, 4136, 4275, 4370, 3149, 5280
Offset: 1

Views

Author

Amarnath Murthy, Sep 22 2002

Keywords

Crossrefs

Cf. A075383, A075384, A075386, A075387, A075389.

Extensions

More terms from David Wasserman, Jan 17 2005

A075387 Product of terms of n-th group in A075383.

Original entry on oeis.org

1, 8, 162, 30720, 562500, 1693052928, 5534208960, 414571718246400, 87954833872105200, 121080960000000000000, 34545810976783666560, 1757453597218363858432819200, 20403194639791728130329600
Offset: 1

Views

Author

Amarnath Murthy, Sep 22 2002

Keywords

Crossrefs

Cf. A075383, A075384, A075385, A075386, A075391.

Programs

Extensions

More terms from David Wasserman, Jan 17 2005

A096780 Inverse of A075383.

Original entry on oeis.org

1, 2, 4, 3, 11, 5, 22, 7, 6, 12, 56, 8, 79, 23, 13, 9, 137, 16, 172, 10, 24, 57, 254, 17, 14, 80, 37, 25, 407, 15, 466, 29, 58, 138, 26, 18, 667, 173, 81, 30, 821, 19, 904, 59, 38, 255, 1082, 20, 27, 46, 139, 82, 1379, 21, 60, 28, 174, 408, 1712, 47, 1831, 467, 39
Offset: 1

Views

Author

Reinhard Zumkeller, Jul 09 2004

Keywords

Comments

Integer permutation: a(A075383(n)) = A075383(a(n)) = n;
A096782(n) = a(a(n)).
For any n > 0, A002024(a(n)) divides n. - Rémy Sigrist, Jan 29 2021

Links

Crossrefs

Cf. A002024, A075383, A096782.

Programs

  • Haskell
    import Data.List (elemIndex); import Data.Maybe (fromJust)
a096780 = (+ 1) . fromJust . (`elemIndex` a075383_list)
-- Reinhard Zumkeller, Nov 29 2015
  • Mathematica
    nmax = 100; 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);
A075383 = Array[row, nmax] // Flatten;
a[n_] := FirstPosition[A075383, n][[1]];
Array[a, nmax] (* Jean-François Alcover, Apr 28 2017 *)

A075388 (1/n) times initial term of n-th group in A075383.

Original entry on oeis.org

1, 1, 1, 2, 1, 3, 1, 4, 3, 5, 1, 7, 1, 7, 5, 8, 1, 9, 1, 10, 7, 11, 1, 13, 5, 13, 9, 14, 1, 17, 1, 16, 11, 17, 7, 19, 1, 19, 13, 23, 1, 21, 1, 22, 17, 23, 1, 29, 7, 25, 17, 26, 1, 27, 11, 29, 19, 29, 1, 37, 1, 31, 23, 37, 13, 33, 1, 37, 23, 37, 1, 41, 1, 37, 25, 41, 11, 41, 1, 47, 27, 41, 1, 53
Offset: 1

Views

Author

Amarnath Murthy, Sep 22 2002

Keywords

Comments

A075384(n)/n

Links

Crossrefs

Cf. A075383, A075384, A075385, A075386.

Programs

Extensions

More terms from David Wasserman, Jan 17 2005

A075390 Average of n-th group in A075383.

Original entry on oeis.org

1, 3, 6, 14, 17, 37, 30, 72, 84, 109, 78, 194, 121, 257, 262, 343, 183, 453, 233, 553, 556, 682, 351, 889, 725, 951, 908, 1145, 570, 1447, 653, 1518, 1397, 1670, 1591, 2105, 978, 2187, 2116, 2737, 1174, 2908, 1333, 2962, 2926, 3071, 1558, 4020, 2887, 3997, 3517
Offset: 1

Views

Author

Amarnath Murthy, Sep 22 2002

Keywords

Links

Crossrefs

Cf. A075383, A075384, A075385, A075386.

Programs

Formula

A075386(n)/n

Extensions

More terms from David Wasserman, Jan 17 2005

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

A075389 (1/n) times final term of n-th group in A075383.

Original entry on oeis.org

1, 2, 3, 5, 6, 9, 8, 13, 14, 16, 14, 22, 18, 26, 26, 30, 22, 35, 25, 39, 39, 43, 31, 50, 44, 51, 50, 57, 40, 65, 43, 67, 62, 68, 68, 79, 53, 79, 79, 90, 58, 94, 62, 94, 95, 95, 67, 110, 91, 109, 102, 113, 76, 122, 110, 126, 115, 123, 85, 144, 89, 132, 138, 144, 134, 151, 98
Offset: 1

Views

Author

Amarnath Murthy, Sep 22 2002

Keywords

Crossrefs

Cf. A075383, A075384, A075385, A075386.

Formula

A075385(n)/n

Extensions

More terms from Sascha Kurz, Jan 28 2003

A263896 Central terms of triangle in A075383.

Original entry on oeis.org

1, 6, 15, 28, 90, 66, 91, 285, 153, 190, 588, 276, 800, 972, 435, 496, 1485, 1750, 703, 2223, 861, 989, 3060, 1175, 3136, 3723, 1431, 4290, 4731, 1829, 2257, 6489, 6175, 2747, 6831, 2627, 2993, 9150, 8547, 4187, 10044, 3901, 10795, 11223, 7921, 11830, 12741
Offset: 1

Views

Author

Reinhard Zumkeller, Nov 29 2015

Keywords

Comments

a(n) = A075383(2*n-1,n).

Crossrefs

Cf. A075383.

Programs

  • Haskell
    a263896 n = a075383 (2 * n - 1) n
Showing 1-10 of 18 results. Next

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