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.

A265183 Base-10 analog of Marko Riedel's A265008, but allowing A, B, C to be zero.

Original entry on oeis.org

1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 8, 3, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 0, 0, 1, 1, 0, 0, 0, 0, 5, 5, 0, 0, 0, 0, 1, 0, 0, 1, 5, 5, 1, 0, 0, 0, 0, 0, 0, 0, 5, 5, 0, 0, 0, 0, 0, 0, 0, 0, 5, 5, 0, 0, 0, 0, 0, 0, 0, 0, 5, 5, 0, 0, 0, 0, 0, 0, 0, 0, 5, 5, 0, 0, 0, 0
Offset: 0

Views

Author

N. J. A. Sloane, Dec 04 2015

Keywords

Crossrefs

Programs

  • Haskell
    a265183 n = length [() | let cs = a218978_row n, a <- cs, b <- cs, c <- cs,
                             a * b == c || c == 0 && a * b == 0]
    -- Reinhard Zumkeller, Dec 05 2015

Extensions

Data corrected by Reinhard Zumkeller, Dec 05 2015

A265182 Base-10 analog of Marko Riedel's A265008.

Original entry on oeis.org

1, 0, 0, 0, 0, 0, 0, 0, 0, 3, 3, 5, 5, 5, 5, 5, 5, 5, 5, 0, 5, 0, 0, 1, 1, 0, 0, 0, 0, 0, 5, 0, 0, 0, 0, 1, 0, 0, 1, 0, 5, 1, 0, 0, 0, 0, 0, 0, 0, 0, 5, 0, 0, 0, 0, 0, 0, 0, 0, 0, 5, 0, 0, 0, 0, 0, 0, 0, 0, 0, 5, 0, 0, 0, 0, 0, 0, 0, 0, 0, 5, 0, 0, 0, 0, 0
Offset: 1

Views

Author

N. J. A. Sloane, Dec 04 2015

Keywords

Crossrefs

See A265183 for the version where A, B, C may be zero.
Cf. A218978.

Programs

  • Haskell
    a265182 n = length [() | let cs = dropWhile (== 0) $ a218978_row n, c <- cs,
                let as = takeWhile (<= c) cs, a <- as, b <- as, a * b == c]
    -- Reinhard Zumkeller, Dec 05 2015
  • Maple
    F:= proc(n) local L, ss;
      L:= convert(n, base, 10);
      ss:= {seq(seq(add(10^(i-j)*L[i], i=j..k), j=1..k), k=1..nops(L))} minus {0};
      numboccur(true, [seq(seq(member(a*b, ss), a=ss), b=ss)]);
    end proc:
    seq(F(n), n=1..1000); # Robert Israel, Dec 06 2015

Extensions

Corrected by Lars Blomberg, Dec 05 2015

A265236 Number of solutions to the equation A x B = C, where A, B and C are nonnegative numbers appearing as (contiguous) substrings of the binary representation of n.

Original entry on oeis.org

1, 1, 8, 3, 13, 12, 18, 5, 19, 17, 18, 20, 31, 26, 28, 7, 26, 23, 23, 26, 31, 22, 32, 28, 47, 40, 38, 34, 49, 40, 38, 9, 34, 30, 29, 31, 31, 31, 38, 34, 47, 39, 28, 34, 53, 40, 46, 38, 66, 55, 54, 48, 59, 46, 46, 48, 75, 62, 58, 52, 67, 58, 48, 11, 43, 38
Offset: 0

Views

Author

Reinhard Zumkeller, Dec 06 2015

Keywords

Comments

A, B and C are allowed to be zero, in contrast to A265008;
a(A000225(n)) = A265008(A000225(n));
a(A062289(n)) != A265008(A062289(n)).

Examples

			.  n | A007088 | A119709     |  a |
. ---+---------+-------------+----+-------------------------------------
.  2 |      10 | [0,1,2]     |  8 = #{(0,0,0), (0,1,0), (0,2,0), (1,0,0),
.    |         |             |        (2,0,0), (1,1,1), (1,2,2), (2,1,2)}
.  3 |      11 | [1,3]       |  3 = #{(1,1,1), (1,3,3), (3,1,3)}
.  4 |     100 | [0,1,2,4]   | 13 = #{(0,0,0), (0,1,0), (0,2,0), (0,4,0),
.    |         |             |         (1,0,0), (2,0,0), (4,0,0), (1,1,1),
.    |         |             |         (1,2,2), (2,1,2), (1,4,4), (2,2,4),
.    |         |             |         (4,1,4)}
.  5 |     101 | [0,1,2,5]   | 12 = #{(0,0,0), (0,1,0), (0,2,0), (0,5,0),
.    |         |             |         (1,0,0), (2,0,0), (5,0,0), (1,1,1),
.    |         |             |         (1,2,2), (2,1,2), (1,5,5), (5,1,5)}
.  6 |     110 | [0,1,2,3,6] | 18 = #{(0,0,0), (0,1,0), (0,2,0), (0,3,0),
.    |         |             |         (0,6,0), (1,0,0), (2,0,0), (3,0,0),
.    |         |             |         (6,0,0), (1,1,1), (1,2,2), (2,1,2),
.    |         |             |         (1,3,3), (3,1,3), (1,6,6), (2,3,6),
.    |         |             |         (3,2,6), (6,1,6)}
.  7 |     111 | [1,3,7]     |≈ 5 = #{(1,1,1), (1,3,3), (3,1,3), (1,7,7),
.    |         |             |         (7,1,7)} .
		

Crossrefs

Programs

  • Haskell
    a265236 n = length [() | let cs = a119709_row n, a <- cs, b <- cs, c <- cs,
                             a * b == c || c == 0 && a * b == 0]

Formula

For n > 0: a(n) = A265008(n) + A043545(n) * (2*A078822(n) - 1).

Extensions

Suggested by N. J. A. Sloane.
Showing 1-3 of 3 results.