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 1-4 of 4 results.

A122543 A122537(n)/n.

Original entry on oeis.org

1, 2, 2, 4, 5, 5, 5, 5, 5, 10, 10, 10, 11, 11, 12, 12, 12, 12, 12, 13, 14, 15, 15, 20, 20, 22, 22, 22, 22, 24, 24, 24, 26, 26, 27, 28, 28, 29, 29, 29, 29, 29, 29, 30, 31, 31, 31, 33, 33, 34, 34, 36, 36, 36, 36, 38, 39, 45, 46, 46, 47, 49, 49, 50, 50, 51, 52, 52, 52, 52, 52, 57, 57, 58, 58
Offset: 1

Views

Author

N. J. A. Sloane and Chao Tian (Chao.Tian(AT)epfl.ch), Sep 19 2006

Keywords

Crossrefs

Cf. A122537.

A122544 Smallest positive number divisible by n which is not of the form a(i) or a(i)+a(j) for i and j <= n-1.

Original entry on oeis.org

1, 4, 3, 12, 10, 18, 35, 32, 9, 40, 55, 48, 26, 84, 105, 112, 17, 54, 76, 100, 231, 198, 23, 120, 25, 156, 162, 280, 203, 150, 31, 192, 264, 68, 245, 288, 222, 418, 468, 440, 82, 294, 301, 352, 405, 368, 141, 432, 98, 600, 714, 520, 424, 702, 275, 672, 513, 928, 177
Offset: 1

Views

Author

N. J. A. Sloane, Sep 20 2006

Keywords

Comments

Same as A122537, except that a(n) is allowed to be less than a(n-1) (but not equal to it, or any other previous term).

Links

Crossrefs

Cf. A122537, A122545 (a(n)/n), A122546 (complement), A122804.

Programs

  • Maple
    a:=array(0..100000); m:=array(0..100000); hit:=array(0..100000); B:=100000; M:=120;
for n from 1 to B do hit[n]:=0; od:
a[1]:=1; m[1]:=1; a[2]:=4; m[2]:=2; hit[2]:=1; hit[5]:=1; hit[8]:=1; hit[1]:=1; hit[4]:=1;
for n from 3 to M do i:=n; while hit[i] = 1 do i:=i+n; od; a[n]:= i; m[n]:= i/n; hit[i]:=1;
for j from 1 to n do hit[a[j]+i]:=1; od; od:
t1:=[seq(a[n],n=1..M)]; t2:=[seq(m[n],n=1..M)];
  • Mathematica
    f[s_] := Block[{n, k},k = n = Length[s] + 1;While[MemberQ[Union[s, Plus @@@ Tuples[s, 2]], k], k += n];Append[s, k]];Nest[f, {1}, 60] (* Ray Chandler, Sep 29 2006 *)

A122804 Smallest positive number divisible by n which is not of the form a(i)+a(j) for i and j <= n-1.

Original entry on oeis.org

1, 4, 3, 12, 10, 12, 21, 32, 9, 40, 55, 48, 26, 28, 45, 112, 17, 108, 114, 180, 63, 132, 23, 168, 150, 104, 270, 28, 145, 150, 186, 128, 99, 170, 70, 252, 370, 266, 39, 400, 328, 252, 301, 352, 495, 92, 188, 576, 245, 150, 408, 468, 106, 486, 165, 784, 342, 406, 649
Offset: 1

Views

Author

Ray Chandler, Sep 23 2006

Keywords

Comments

Same as A122544, except that a(n) is allowed to take values already in the sequence.

Links

Crossrefs

Cf. A122537, A122544, A122805 (a(n)/n), A122806 (complement).

Programs

  • Mathematica
    f[s_] := Block[{n, k},k = n = Length[s] + 1;While[MemberQ[Union[Plus @@@ Tuples[s, 2]], k], k += n];Append[s, k]];Nest[f, {1}, 60]

A242251 Smallest positive number divisible by n which is not of the form a(i), a(i)+a(j), or |a(i)-a(j)| for i and j <= n-1.

Original entry on oeis.org

1, 4, 6, 16, 25, 18, 28, 40, 45, 30, 11, 72, 13, 84, 105, 64, 119, 126, 57, 140, 273, 220, 23, 240, 225, 52, 405, 196, 174, 390, 93, 160, 363, 476, 455, 288, 37, 152, 429, 520, 656, 714, 172, 308, 585, 184, 517, 624, 735, 600, 612, 208, 848, 756, 605, 1288
Offset: 1

Views

Author

J. Lowell, May 09 2014

Keywords

Comments

Same as A122544, except that both sums and absolute differences of previous terms are disqualified.

Examples

			a(3) cannot be 3 because 3 = 4-1 and 1 and 4 are both previous terms.

Links

Crossrefs

Cf. A122537, A122544.
Showing 1-4 of 4 results.

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

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