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 1-3 of 3 results.

A362326 Pairs (i, j) of nonnegative integers whose ternary expansions have no common digit 1 sorted first by i + j then by i.

Original entry on oeis.org

0, 0, 0, 1, 1, 0, 0, 2, 2, 0, 0, 3, 1, 2, 2, 1, 3, 0, 0, 4, 1, 3, 2, 2, 3, 1, 4, 0, 0, 5, 2, 3, 3, 2, 5, 0, 0, 6, 1, 5, 2, 4, 4, 2, 5, 1, 6, 0, 0, 7, 1, 6, 2, 5, 5, 2, 6, 1, 7, 0, 0, 8, 2, 6, 6, 2, 8, 0, 0, 9, 1, 8, 2, 7, 3, 6, 6, 3, 7, 2, 8, 1, 9, 0, 0, 10
Offset: 1

Views

Author

Rémy Sigrist, Apr 16 2023

Keywords

Comments

This sequence is to Sierpinski carpet what A352909 is to Sierpinski gasket.
There are A293974(n + 1) pairs (i, j) with n = i + j.
See A362329 for the other pairs.

Examples

			The first pairs are:
    (0, 0),
    (0, 1), (1, 0),
    (0, 2), (2, 0),
    (0, 3), (1, 2), (2, 1), (3, 0),
    (0, 4), (1, 3), (2, 2), (3, 1), (4, 0),
    (0, 5), (2, 3), (3, 2), (5, 0),
    (0, 6), (1, 5), (2, 4), (4, 2), (5, 1), (6, 0),
    (0, 7), (1, 6), (2, 5), (5, 2), (6, 1), (7, 0),
    (0, 8), (2, 6), (6, 2), (8, 0),
    ...
		

Crossrefs

Cf. A293974, A352909, A362327 (i-values), A362328 (j-values), A362329 (complement).

Programs

  • PARI
    is(i, j) = { while (i && j, if (i%3==1 && j%3==1, return (0), i\=3; j\=3;);); return (1); }
    row(ij) = apply (i -> [i, ij-i], select(i -> is(i, ij-i), [0..ij]))

A362328 The j-values of pairs (i, j) listed in A362326.

Original entry on oeis.org

0, 1, 0, 2, 0, 3, 2, 1, 0, 4, 3, 2, 1, 0, 5, 3, 2, 0, 6, 5, 4, 2, 1, 0, 7, 6, 5, 2, 1, 0, 8, 6, 2, 0, 9, 8, 7, 6, 3, 2, 1, 0, 10, 9, 8, 7, 6, 4, 3, 2, 1, 0, 11, 9, 8, 6, 5, 3, 2, 0, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3
Offset: 1

Views

Author

Rémy Sigrist, Apr 16 2023

Keywords

Comments

See A362327 for the i-values.

Crossrefs

Cf. A362326, A362327 (i-values).

Programs

  • PARI
    is(i, j) = { while (i && j, if (i%3==1 && j%3==1, return (0), i\=3; j\=3;);); return (1); }
    row(ij) = apply (i -> ij-i, select(i -> is(i, ij-i), [0..ij]))

A363930 Irregular table T(n, k), n >= 0, k = 1..A363710(n), read by rows; the n-th row lists the nonnegative numbers m <= n such that A003188(m) AND A003188(n-m) = 0 (where AND denotes the bitwise AND operator).

Original entry on oeis.org

0, 0, 1, 0, 2, 0, 3, 0, 1, 3, 4, 0, 1, 4, 5, 0, 6, 0, 7, 0, 1, 7, 8, 0, 1, 2, 3, 6, 7, 8, 9, 0, 2, 3, 7, 8, 10, 0, 3, 8, 11, 0, 1, 3, 9, 11, 12, 0, 1, 12, 13, 0, 14, 0, 15, 0, 1, 15, 16, 0, 1, 2, 3, 14, 15, 16, 17, 0, 2, 3, 4, 6, 12, 14, 15, 16, 18, 0, 3, 4, 7, 12, 15, 16, 19
Offset: 0

Views

Author

Rémy Sigrist, Jun 28 2023

Keywords

Comments

This sequence is related to the T-square fractal (see A363710).

Examples

			Table T(n, k) begins:
  n   n-th row
  --  ----------------------
   0  0
   1  0, 1
   2  0, 2
   3  0, 3
   4  0, 1, 3, 4
   5  0, 1, 4, 5
   6  0, 6
   7  0, 7
   8  0, 1, 7, 8
   9  0, 1, 2, 3, 6, 7, 8, 9
  10  0, 2, 3, 7, 8, 10
  11  0, 3, 8, 11
  12  0, 1, 3, 9, 11, 12
  13  0, 1, 12, 13
  14  0, 14
  15  0, 15
  16  0, 1, 15, 16
		

Crossrefs

See A295989, A353174 and A362327 for similar sequences.

Programs

  • PARI
    row(n) = { select (m -> bitand(bitxor(m, m\2), bitxor(n-m, (n-m)\2))==0, [0..n]) }

Formula

T(n, 1) = 0.
T(n, A363710(n)) = n.
T(n, k) + T(n, A363710(n)+1-k) = n.
Showing 1-3 of 3 results.