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.

A276784 Complement of A276783.

Original entry on oeis.org

1, 2, 5, 8, 9, 10, 11, 12, 15, 20, 21, 24, 25, 26, 27, 28, 31, 32, 35, 36, 37, 38, 41, 46, 47, 50, 51, 52, 54, 56, 57, 60, 63, 65, 66, 69, 70, 72, 73, 74, 75, 78, 79, 82, 83, 86, 87, 90, 91, 96, 97, 98, 99, 101, 103, 104, 106, 108, 109, 111, 114, 116, 117, 120, 123, 125, 128, 129, 130, 132, 133, 136, 139, 140, 141, 144, 145, 148, 149, 150, 151, 153, 155
Offset: 1

Views

Author

N. J. A. Sloane, Oct 03 2016

Keywords

Links

Crossrefs

Cf. A275901, A275902, A276783.

A275901 Following the successive antidiagonals in A275895, let the n-th queen appear in square (x(n),y(n)); sequence gives x(n).

Original entry on oeis.org

0, 1, 3, 2, 4, 5, 9, 6, 10, 12, 7, 8, 14, 11, 19, 20, 13, 15, 25, 16, 26, 28, 17, 18, 30, 33, 21, 22, 37, 23, 39, 24, 42, 41, 27, 29, 48, 49, 31, 32, 53, 55, 34, 35, 58, 57, 36, 38, 63, 40, 66, 68, 43, 70, 44, 45, 74, 46, 76, 47, 77, 79, 50, 51, 84, 52, 85, 54, 89, 90, 56, 94, 59, 60, 98, 61, 100, 62
Offset: 0

Views

Author

N. J. A. Sloane, Aug 24 2016

Keywords

Comments

See A275902 for y(n).
This is a permutation of the nonnegative numbers.
This assumes the indexing starts at 0. See A275899, A275900 if the indexing begins at 1.

Links

Crossrefs

Cf. A065188, A275895, A275899, A275900, A275902.

Programs

  • Maple
    See A275899.
# Alternative Maple program from N. J. A. Sloane, Oct 03 2016
# To get 10000 terms of A275902 (xx), A275901 (yy), A276783 (ss), -A276325 (dd)
M1:=100000; M2:=22000; M3:=10000;
xx:=Array(0..M1,0); yy:=Array(0..M1,0); ss:=Array(0..M1,0); dd:=Array(0..M1,0);
xx[0]:=0; yy[0]:=0; ss[0]:=0; dd[0]:=0;
for n from 1 to M2 do
sw:=-1;
   for s from ss[n-1]+1 to M2 do
      for i from 0 to s do
         x:=s-i; y:=i;
         if not member(x,xx,'p') and
            not member(y,yy,'p') and
            not member(x-y,dd,'p') then sw:=1; break; fi;
      od:  # od i
if sw=1 then break; fi;
   od: # od s
  if sw=-1 then lprint("error, n=",n); break; fi;
xx[n]:=x; yy[n]:=y; ss[n]:=x+y; dd[n]:=x-y;
od: # od n
[seq(xx[i],i=0..M3)]:
[seq(yy[i],i=0..M3)]:
[seq(ss[i],i=0..M3)]:
[seq(dd[i],i=0..M3)]:

A275902 Following the successive antidiagonals in A275895, let the n-th queen appear in square (x(n),y(n)); sequence gives y(n).

Original entry on oeis.org

0, 2, 1, 4, 3, 8, 5, 10, 7, 6, 12, 14, 9, 18, 11, 13, 21, 24, 15, 26, 17, 16, 28, 30, 19, 20, 34, 36, 22, 38, 23, 40, 25, 27, 44, 47, 29, 31, 50, 52, 32, 33, 55, 57, 35, 37, 59, 62, 39, 65, 41, 42, 69, 43, 71, 73, 45, 75, 46, 77, 49, 48, 81, 83, 51, 85, 53, 88, 54, 56, 91, 58, 95, 97, 60, 99, 61, 101
Offset: 0

Views

Author

N. J. A. Sloane, Aug 24 2016

Keywords

Comments

See A275901 for x(n).
This is a permutation of the nonnegative numbers.
This assumes the indexing starts at 0. See A275899, A275900 if the indexing begins at 1.

Links

Crossrefs

Cf. A065188, A275895, A275899, A275900, A275901.

Programs

  • Maple
    See A275899.
# Alternative Maple program from N. J. A. Sloane, Oct 03 2016
# To get 10000 terms of A275902 (xx), A275901 (yy), A276783 (ss), -A276325 (dd)
M1:=100000; M2:=22000; M3:=10000;
xx:=Array(0..M1,0); yy:=Array(0..M1,0); ss:=Array(0..M1,0); dd:=Array(0..M1,0);
xx[0]:=0; yy[0]:=0; ss[0]:=0; dd[0]:=0;
for n from 1 to M2 do
sw:=-1;
   for s from ss[n-1]+1 to M2 do
      for i from 0 to s do
         x:=s-i; y:=i;
         if not member(x,xx,'p') and
            not member(y,yy,'p') and
            not member(x-y,dd,'p') then sw:=1; break; fi;
      od:  # od i
if sw=1 then break; fi;
   od: # od s
  if sw=-1 then lprint("error, n=",n); break; fi;
xx[n]:=x; yy[n]:=y; ss[n]:=x+y; dd[n]:=x-y;
od: # od n
[seq(xx[i],i=0..M3)]:
[seq(yy[i],i=0..M3)]:
[seq(ss[i],i=0..M3)]:
[seq(dd[i],i=0..M3)]:

A276325 Diagonal indices of Greedy Queens (see A065188).

Original entry on oeis.org

0, -1, 2, -2, 1, -3, 4, -4, 3, 6, -5, -6, 5, -7, 8, 7, -8, -9, 10, -10, 9, 12, -11, -12, 11, 13, -13, -14, 15, -15, 16, -16, 17, 14, -17, -18, 19, 18, -19, -20, 21, 22, -21, -22, 23, 20, -23, -24, 24, -25, 25, 26, -26, 27, -27, -28, 29, -29, 30, -30, 28, 31
Offset: 1

Views

Author

Alois P. Heinz, Aug 30 2016

Keywords

Comments

a(n) is the index of the diagonal of the n-th queen. The main diagonal has index 0, upper (lower) diagonals have positive (negative) indices.

Examples

			The first queen is in the main diagonal, the second queen is in the first lower diagonal, the third queen is in the second upper diagonal, ... :
:
:  Q\\\\ ...
:  \\\Q\ ...
:  \Q\\\ ...
:  \\\\Q ...
:  \\Q\\ ...
:  \\\\\ ...
:  .....

Links

Crossrefs

Cf. A065188, A276324, A275901, A275902.

Programs

  • Maple
    # Maple program from N. J. A. Sloane, Oct 03 2016
# To get 10000 terms of A275902 (xx), A275901 (yy), A276783 (ss), -A276325 (dd)
M1:=100000; M2:=22000; M3:=10000;
xx:=Array(0..M1,0); yy:=Array(0..M1,0); ss:=Array(0..M1,0); dd:=Array(0..M1,0);
xx[0]:=0; yy[0]:=0; ss[0]:=0; dd[0]:=0;
for n from 1 to M2 do
sw:=-1;
   for s from ss[n-1]+1 to M2 do
      for i from 0 to s do
         x:=s-i; y:=i;
         if not member(x,xx,'p') and
            not member(y,yy,'p') and
            not member(x-y,dd,'p') then sw:=1; break; fi;
      od:  # od i
if sw=1 then break; fi;
   od: # od s
  if sw=-1 then lprint("error, n=",n); break; fi;
xx[n]:=x; yy[n]:=y; ss[n]:=x+y; dd[n]:=x-y;
od: # od n
[seq(xx[i],i=0..M3)]:
[seq(yy[i],i=0..M3)]:
[seq(ss[i],i=0..M3)]:
[seq(dd[i],i=0..M3)]:

Formula

Equals A275901 - A275902.
Showing 1-4 of 4 results.

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

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