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 13 results. Next

A104663 Position of n in A105822.

Original entry on oeis.org

1, 2, 3, 6, 4, 11, 8, 5, 26, 9, 12, 7, 15, 17, 33, 43, 10, 25, 16, 19, 13, 32, 39, 21, 61, 175, 22, 20, 57, 37, 95, 14, 18, 50, 27, 40, 34, 110, 29, 24, 171, 23, 64, 28, 46, 203, 45, 31, 137, 91, 134, 35, 58, 30, 90, 54, 69, 106, 38, 73, 360, 296, 67, 88, 48, 70, 526, 109, 124
Offset: 1

Views

Author

Zak Seidov, Apr 22 2005

Keywords

Comments

Is A105822 a permutation of the positive integers?

Crossrefs

Cf. A105822.

Programs

  • Maple
    N:= 1000: # to go up to the first entry missing in A105822(1 .. N)
    A:= 'A':
    a[1]:= 1: a[2]:= 2:
    A[1]:= 1: A[2]:= 2:
    for n from 3 to N do
      ds:= map(t -> rhs(op(t)), [msolve(x^2=a[n-1]^2, 4*a[n-2])]);
      xmin:= infinity;
      for d in ds do
        found:= false;
        for y from floor((a[n-1]-d)/(4*a[n-2]))+1 do
          xy:= 4*a[n-2]*y + d;
          cand:= (xy^2 - a[n-1]^2)/(4*a[n-2]);
          if cand >= xmin then found:= false; break fi;
          if not assigned(A[cand]) then found:= true; break fi;
        od:
        if found then xmin:= cand;  fi;
      od:
      a[n]:= xmin;
      A[xmin]:= n;
    od:
    M:= min(select(t -> not assigned(A[t]), [$1..N+1])):
    seq(A[i],i=1..M-1); # Robert Israel, May 11 2015

Extensions

Definition corrected by N. J. A. Sloane, Aug 29 2008

A105823 Perfect squares in A105822.

Original entry on oeis.org

16, 49, 121, 144, 400, 256, 529, 576, 529, 784, 625, 1849, 2116, 2601, 1089, 2704, 2209, 4096, 2704, 3600, 4761, 6084, 4624, 1764, 2601, 2809, 7396, 11025, 10404, 7056, 3364, 3481, 4489, 15876, 14161, 21904, 6241, 9025, 10404, 19881, 11236
Offset: 1

Views

Author

Zak Seidov, Apr 22 2005

Keywords

Crossrefs

Cf. A105822.

Formula

a(n)=A105822(n+1)^2+4*A105822(n)*A105822(n+2)

A104664 Records in A105822.

Original entry on oeis.org

1, 2, 3, 5, 8, 12, 17, 21, 32, 33, 42, 44, 54, 89, 99, 157, 222, 236, 258, 327, 345, 371, 470, 495, 606, 634, 866, 891, 1219, 1383, 1540, 1626, 1660, 1878, 1989, 2064, 2758, 3534, 3954, 4053, 4113, 4468, 4618, 4783, 4862, 5134, 6394, 7176, 7480, 11649
Offset: 1

Views

Author

Zak Seidov, Apr 22 2005

Keywords

Comments

Is A105822 a permutation of positive integers?

Crossrefs

Cf. A105822.

A104665 Positions of records in A105822.

Original entry on oeis.org

1, 2, 3, 4, 5, 7, 10, 13, 14, 18, 23, 28, 30, 36, 41, 49, 53, 77, 85, 102, 114, 141, 151, 163, 174, 182, 188, 244, 263, 311, 419, 434, 468, 477, 478, 655, 656, 739, 768, 890, 1002, 1027, 1099, 1118, 1166, 1365, 1397, 1440, 1574, 1575
Offset: 1

Views

Author

Zak Seidov, Apr 22 2005

Keywords

Comments

Is A105822 a permutation of positive integers?

Crossrefs

Cf. A105822.

A105836 For n>2, a(n) not appeared previously is such that a(n-1)^2+4*a(n-2)*a(n) is a minimal square, a(1)=2, a(2)=3.

Original entry on oeis.org

2, 3, 5, 8, 4, 12, 7, 10, 17, 6, 11, 21, 32, 13, 19, 14, 33, 20, 28, 24, 27, 42, 40, 18, 1, 39, 82, 72, 154, 43, 35, 78, 56, 22, 9, 31, 70, 69, 52, 25, 48, 73, 46, 119, 57, 26, 15, 36, 51, 50, 101, 60, 41, 54, 95, 61, 16, 45, 76, 121, 62, 59, 130, 141, 81, 222, 63, 87, 30, 117
Offset: 1

Views

Author

Zak Seidov, Apr 22 2005

Keywords

Crossrefs

A105828 For n>2, a(n) not appeared previously is such that a(n-1)^2+4*a(n-2)*a(n) is a minimal square, a(1)=1, a(2)=3.

Original entry on oeis.org

1, 3, 4, 7, 2, 5, 12, 9, 21, 8, 13, 6, 19, 11, 30, 41, 15, 26, 24, 50, 14, 36, 18, 10, 28, 38, 66, 20, 16, 48, 45, 93, 72, 165, 63, 102, 96, 198, 105, 23, 62, 85, 58, 27, 31, 46, 32, 78, 47, 43, 90, 117, 22, 95, 53, 42, 128, 40, 25, 65, 68, 124, 79, 129, 208, 100, 108, 184, 64
Offset: 1

Views

Author

Zak Seidov, Apr 22 2005

Keywords

Crossrefs

A105835 For n>2, a(n) not appeared previously is such that a(n-1)^2+4*a(n-2)*a(n) is a minimal square, a(1)=1, a(2)=10.

Original entry on oeis.org

1, 10, 11, 6, 5, 4, 9, 13, 22, 8, 14, 15, 26, 21, 17, 30, 47, 19, 28, 20, 33, 27, 60, 7, 2, 24, 56, 34, 12, 46, 36, 82, 50, 32, 18, 45, 38, 35, 3, 54, 57, 25, 42, 16, 58, 63, 106, 40, 66, 43, 23, 126, 72, 104, 70, 61, 39, 100, 51, 49, 156, 160, 31, 129, 130, 144, 162, 81, 68
Offset: 1

Views

Author

Zak Seidov, Apr 22 2005

Keywords

Crossrefs

A105829 For n>2, a(n) not appeared previously is such that a(n-1)^2+4*a(n-2)*a(n) is a minimal square, a(1)=1, a(2)=4.

Original entry on oeis.org

1, 4, 5, 6, 8, 14, 9, 18, 7, 11, 30, 41, 15, 26, 21, 17, 38, 39, 27, 12, 20, 13, 33, 46, 19, 2, 72, 74, 23, 51, 54, 96, 24, 36, 60, 56, 32, 78, 47, 10, 37, 65, 102, 167, 67, 100, 68, 59, 105, 164, 45, 119, 48, 71, 29, 42, 135, 132, 3, 129, 270, 351, 66, 40, 64, 90, 61, 53, 114
Offset: 1

Views

Author

Zak Seidov, Apr 22 2005

Keywords

Crossrefs

A105834 For n>2, a(n) not appeared previously is such that a(n-1)^2+4*a(n-2)*a(n) is a minimal square, a(1)=1, a(2)=9.

Original entry on oeis.org

1, 9, 10, 16, 8, 3, 5, 2, 7, 4, 11, 15, 14, 29, 18, 47, 21, 26, 32, 40, 12, 28, 17, 6, 23, 13, 36, 49, 46, 95, 50, 45, 35, 80, 75, 155, 22, 69, 76, 33, 43, 20, 63, 68, 91, 27, 64, 51, 115, 44, 71, 34, 37, 62, 24, 38, 25, 48, 73, 70, 143, 60, 83, 19, 102, 72, 30, 42, 144, 96, 65
Offset: 1

Views

Author

Zak Seidov, Apr 22 2005

Keywords

Crossrefs

A105830 For n>2, a(n) not appeared previously is such that a(n-1)^2+4*a(n-2)*a(n) is a minimal square, a(1)=1, a(2)=5.

Original entry on oeis.org

1, 5, 6, 8, 14, 4, 10, 24, 18, 15, 3, 12, 36, 21, 2, 19, 33, 52, 28, 27, 55, 78, 16, 62, 35, 87, 54, 141, 25, 46, 71, 42, 29, 13, 90, 7, 26, 45, 50, 80, 40, 75, 115, 58, 57, 43, 44, 84, 53, 22, 31, 60, 91, 37, 20, 17, 63, 110, 32, 96, 56, 132, 108, 135, 138, 61, 65, 114, 143, 100
Offset: 1

Views

Author

Zak Seidov, Apr 22 2005

Keywords

Crossrefs

Showing 1-10 of 13 results. Next