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 1-7 of 7 results.

A250983 First differences of A094589.

Original entry on oeis.org

1, 2, 2, 4, 4, 6, 6, 6, 6, 10, 10, 10, 10, 14, 14, 14, 14, 14, 14, 20, 20, 20, 20, 20, 20, 26, 26, 26, 26, 26, 26, 32, 32, 32, 32, 32, 32, 38, 38, 38, 38, 38, 38, 38, 38, 38, 38, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 58, 58, 58, 58, 58, 58, 58, 58, 58, 58
Offset: 1

Views

Author

Ivan Neretin, Mar 20 2015

Keywords

Comments

Also, a Golomb-type sequence over A094589, i.e., a sequence obtained from A094589 by repeating each term a certain number of times so that the succession of run lengths of the resulting sequence is again that same sequence.
Has the property of idempotence: a(a(n))=a(n).

Crossrefs

Cf. A094589 (a(n) with repetitions removed), A001462 (Golomb's sequence), A013189 (Golomb's sequence over squares).

Programs

  • Mathematica
    w = {1, 2, 2};
    i = 3;
    Do[
      w = Join[w, Array[Length[w] + 1 &, w[[i++]]]];
      , {n, 10}
      ];
    w
  • PARI
    flargest(va, n) = {vsa = vecsort(va,,12); for (k=1, #vsa, if (vsa[k] < n, return (vsa[k])););}
    lista(nn) = {voa = [1]; for (n=2, nn, newoa = flargest(voa, n) + voa[n-1]; print1(newoa - voa[n-1], ", "); voa = concat(voa, newoa););} \\ Michel Marcus, Mar 24 2015

Extensions

More terms from Michel Marcus, Mar 24 2015

A118026 a(0) = 0, a(n) = a(n-1) + (largest integer which is <= n and is missing from the earlier terms of the sequence).

Original entry on oeis.org

0, 1, 3, 5, 9, 13, 19, 26, 34, 42, 52, 63, 75, 87, 101, 116, 132, 149, 167, 185, 205, 226, 248, 271, 295, 320, 345, 372, 400, 429, 459, 490, 522, 555, 588, 623, 659, 696, 734, 773, 813, 854, 895, 938, 982, 1027, 1073, 1120, 1168, 1217, 1267, 1318, 1369, 1422
Offset: 0

Views

Author

Leroy Quet, Apr 10 2006

Keywords

Crossrefs

Programs

  • Mathematica
    a = {1}; Do[AppendTo[a, a[[i - 1]] + SelectFirst[Reverse@ Range[i], FreeQ[a, #] &]], {i, 2, 53}]; {0}~Join~a (* Michael De Vlieger, Sep 16 2017 *)

Extensions

More terms from Sheedeh Dorri (spd145(AT)psu.edu) and Melissa Donovan (msd181(AT)psu.edu), Apr 18 2006

A118027 a(0) = 0, a(n) = a(n-1) + (smallest integer which is >= n and is missing from the earlier terms of the sequence).

Original entry on oeis.org

0, 1, 3, 7, 11, 16, 22, 30, 38, 47, 57, 69, 81, 94, 108, 123, 140, 157, 175, 194, 214, 235, 258, 281, 305, 330, 356, 383, 411, 440, 471, 502, 534, 567, 601, 636, 672, 709, 748, 787, 827, 868, 910, 953, 997, 1042, 1088, 1136, 1184, 1233, 1283, 1334, 1386, 1439
Offset: 0

Views

Author

Leroy Quet, Apr 10 2006

Keywords

Crossrefs

Programs

  • Mathematica
    a = {1}; Do[k = i; While[MemberQ[a, k], k++]; AppendTo[a, a[[i - 1]] + k], {i, 2, 53}]; {0}~Join~a (* Michael De Vlieger, Sep 16 2017 *)

Extensions

More terms from Wendy Kalasky (wkk107(AT)psu.edu), Apr 26 2006

A118028 a(0)=1. a(n) = a(n-1) + (smallest integer which is >= n and is missing from the earlier terms of the sequence).

Original entry on oeis.org

1, 3, 5, 9, 13, 19, 25, 32, 40, 50, 60, 71, 83, 97, 111, 126, 142, 159, 177, 197, 217, 238, 260, 283, 307, 333, 359, 386, 414, 443, 473, 504, 537, 570, 604, 639, 675, 712, 750, 789, 830, 871, 913, 956, 1000, 1045, 1091, 1138, 1186, 1235, 1286, 1337, 1389, 1442
Offset: 0

Views

Author

Leroy Quet, Apr 10 2006

Keywords

Crossrefs

Programs

  • Mathematica
    a = {1}; Do[k = 2; While[Nand[FreeQ[a, k], k >= i], k++]; AppendTo[a, a[[i]] + k], {i, 53}]; a (* Michael De Vlieger, Sep 19 2017 *)

Extensions

More terms from Joshua Zucker, Jul 27 2006

A118029 a(0)=1. a(n) = a(n-1) + (smallest integer that is >= n and occurs among the earlier terms of the sequence).

Original entry on oeis.org

1, 2, 4, 8, 12, 20, 28, 36, 44, 56, 68, 80, 92, 112, 132, 152, 172, 192, 212, 232, 252, 280, 308, 336, 364, 392, 420, 448, 476, 512, 548, 584, 620, 656, 692, 728, 764, 808, 852, 896, 940, 984, 1028, 1072, 1116, 1172, 1228, 1284, 1340, 1396, 1452, 1508, 1564
Offset: 0

Views

Author

Leroy Quet, Apr 10 2006

Keywords

Comments

Let b_j(n) = 2*n*(n/2)^(2^(-j))/(1+2^(-j)). For any positive integers r and n, we have (n^2+n)/2 < a(n) < b_r(n) + Sum_{j=1..r} b_j(n). - Colin Defant, Sep 15 2015

Crossrefs

Programs

  • Mathematica
    a = {1}; Do[k = 1; While[Nand[MemberQ[a, k], k >= i], k++]; AppendTo[a, a[[i]] + k], {i, 52}]; a (* Michael De Vlieger, Sep 19 2017 *)
  • PARI
    lista(nn) = {va = vector(nn); va[1] = 1; for (k=2, nn, vs = select(x->(x >= k-1), va, 1); va[k] = va[k-1] + va[vs[1]];); va;} \\ Michel Marcus, Oct 09 2015

Extensions

More terms from Adam Panagos (adam.panagos(AT)gmail.com), May 10 2006
More terms from Joshua Zucker, Jul 27 2006

A118030 a(1)=1. a(n) = a(n-1) + (largest integer which is <= n and occurs among the earlier terms of the sequence).

Original entry on oeis.org

1, 2, 4, 8, 12, 16, 20, 28, 36, 44, 52, 64, 76, 88, 100, 116, 132, 148, 164, 184, 204, 224, 244, 264, 284, 304, 324, 352, 380, 408, 436, 464, 492, 520, 548, 584, 620, 656, 692, 728, 764, 800, 836, 880, 924, 968, 1012, 1056, 1100, 1144, 1188, 1240, 1292, 1344, 1396, 1448, 1500, 1552, 1604, 1656, 1708, 1760
Offset: 1

Views

Author

Leroy Quet, Apr 10 2006

Keywords

Crossrefs

Programs

  • Mathematica
    a = {1}; Do[k = i + 1; While[Nand[MemberQ[a, k], k <= i + 1], k--]; AppendTo[a, a[[i]] + k], {i, 61}]; a (* Michael De Vlieger, Sep 19 2017 *)

Extensions

More terms from Melissa Donovan (msd181(AT)psu.edu), Apr 23 2006

A094590 a(1) = 1; a(n+1) = a(n) * k(n), where k(n) is the number of elements of {a(j)}, 1<=j<=n, which are <= n.

Original entry on oeis.org

1, 1, 2, 6, 18, 54, 216, 864, 3456, 13824, 55296, 221184, 884736, 3538944, 14155776, 56623104, 226492416, 905969664, 4529848320, 22649241600, 113246208000, 566231040000, 2831155200000, 14155776000000, 70778880000000
Offset: 1

Views

Author

Leroy Quet, Jun 07 2004

Keywords

Crossrefs

Cf. A094589.

Extensions

More terms from Vladeta Jovovic, Jun 13 2004
Showing 1-7 of 7 results.