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 1-6 of 6 results.

A125991 A106486-encodings of combinatorial games with zero value.

Original entry on oeis.org

0, 8, 16, 24, 64, 72, 80, 88, 128, 136, 144, 152, 192, 200, 208, 216, 512, 520, 528, 536, 576, 584, 592, 600, 640, 648, 656, 664, 704, 712, 720, 728, 2048, 2056, 2064, 2072, 2112, 2120, 2128, 2136, 2176, 2184, 2192, 2200, 2240, 2248, 2256, 2264
Offset: 1

Views

Author

Antti Karttunen, Dec 18 2006

Keywords

Comments

In these games, the second player can always win.

Examples

			Game 0 is encoded as zero, giving the first term of this sequence. Also 24 belongs into this sequence, as it encodes game {-1|1}, which the second player always wins. Similarly for game {*|*} which has code 2^(1+2*3) + 2^(2*3) = 192, thus 192 is a member of this sequence.
		

Crossrefs

Row 1 of A126000. Intersection of A126001 and A126002. Characteristic function occurs as row 0 of A126010.

A079599 Numbers n for which the n-th impartial game is a second player win.

Original entry on oeis.org

0, 2, 8, 10, 16, 18, 24, 26, 32, 34, 40, 42, 48, 50, 56, 58, 64, 66, 72, 74, 80, 82, 88, 90, 96, 98, 104, 106, 112, 114, 120, 122, 128, 130, 136, 138, 144, 146, 152, 154, 160, 162, 168, 170, 176, 178, 184, 186, 192, 194, 200, 202, 208, 210, 216, 218, 224, 226, 232, 234, 240, 242, 248, 250, 512, 514
Offset: 0

Views

Author

Rob Arthan, Jan 28 2003

Keywords

Comments

These are the indices n for which A034798(n) = 0.
From Antti Karttunen, Jan 30 2014: (Start)
A236678(a(n)) = n+1 for all n.
Differs from A047467 for the first time at a(64).
Differs from A126002(n+1) for the first time not later than at n=281474976710656 (= 2^48), as:
a((2^48)-1) = a(281474976710655) = 18085043209519168250 < 18446744073709551616 (= 2^64), while
a(2^48) = a(281474976710656) = 36893488147419103232 > 2^64.
(End)

Examples

			a(1) = 2 (rather than 1) because 1 = 2^0 = 2^a(0); a(64) = 512 (rather than 256) because 256 = 2^8 = 2^a(2).
		

References

  • J. H. Conway, On numbers and games.

Crossrefs

Characteristic function: A236677, its partial sums: A236678.

Programs

  • Scheme
    (define (A079599 n) (let loop ((n n) (i 0) (j 0) (s 0)) (cond ((zero? n) s) ((odd? n) (loop (/ (- n 1) 2) (+ i 1) (+ j 1 (A236677 j)) (+ s (expt 2 (+ j (A236677 j)))))) (else (loop (/ n 2) (+ i 1) (+ j 1 (A236677 j)) s)))))

Formula

a(0) = 0; a(n+1) = least x > a(n) such that the coefficient of 2^a(j) is zero in the binary expansion of x for all j < n+1
Alternatively: rewrite the binary representation of n in such a way that the forbidden bit-positions given by this sequence (with bit-position 0 standing for the least significant bit) are vacated, by shifting the rest of bits one bit left. E.g., bit-positions 0, 2, 8, 10, ... are forbidden, thus we rewrite 1 to 1x = 10 = 2, 2 (in binary 10) to 1x0x = 1000 = 8, 3 (in binary 11) to 1x1x = 1010 = 10, 4 (in binary 100) to 10x0x = 1000 = 16, 64 (in binary 1000000) to 1x00000x0x = 1000000000 = 512, etc. - Antti Karttunen, Jan 30 2014

Extensions

More terms from Antti Karttunen, Jan 29 2014

A125999 Square array A(g,h) = 1 if combinatorial game g has value greater than or equal to that of game h, otherwise 0, listed antidiagonally in order A(0,0), A(1,0), A(0,1), A(2,0), A(1,1), A(0,2), ...

Original entry on oeis.org

1, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 0, 1, 1, 0, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 1, 0, 1, 1, 1, 0, 0, 0, 1, 1, 0, 1, 1, 1, 1, 0, 0, 1, 0, 0, 0, 1, 1, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 1, 0, 1, 0, 1, 1, 0, 0, 1, 1, 1, 0, 1, 1, 0, 1, 0, 1, 0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 1, 0, 1, 1, 1, 0, 0, 0
Offset: 0

Views

Author

Antti Karttunen, Dec 18 2006

Keywords

Comments

Here we use the encoding explained in A106486. A(i,j) = A(A106485(j),A106485(i)).

Crossrefs

Row 0 is the characteristic function of A126001 (shifted one step) and similarly, column 0 is the characteristic function of A126002. Cf. tables A126010 and A126000.

A126003 A106486-encodings of combinatorial games whose value is incomparable with zero game, i.e., fuzzy games.

Original entry on oeis.org

3, 6, 7, 11, 14, 15, 19, 22, 23, 27, 30, 31, 33, 35, 36, 37, 38, 39, 41, 43, 44, 45, 46, 47, 49, 51, 52, 53, 54, 55, 57, 59, 60, 61, 62, 63, 67, 70, 71, 75, 78, 79, 83, 86, 87, 91, 94, 95, 97, 99, 100, 101, 102, 103, 105, 107, 108, 109, 110, 111, 113, 115, 116, 117, 118
Offset: 1

Views

Author

Antti Karttunen, Dec 18 2006

Keywords

Comments

In these games, the first player can always win.

Crossrefs

Intersection of the complements of A126001 and A126002, or equally, complement of the union of A126001 and A126002. Differs from A047556. Cf. A125991, A125994, A126004-A126005.

A126005 A106486-encodings of combinatorial games whose value is less than zero.

Original entry on oeis.org

2, 10, 18, 26, 32, 34, 40, 42, 48, 50, 56, 58, 66, 74, 82, 90, 96, 98, 104, 106, 112, 114, 120, 122, 130, 138, 146, 154, 160, 162, 168, 170, 176, 178, 184, 186, 194, 202, 210, 218, 224, 226, 232, 234, 240, 242, 248, 250, 514, 522, 530, 538, 544, 546, 552, 554
Offset: 1

Views

Author

Antti Karttunen, Dec 18 2006

Keywords

Comments

In these games, the right can always win.

Crossrefs

Intersection of complement of A126001 and A126002. Cf. A125991, A126001-A126003.

A126004 A106486-encodings of combinatorial games whose value is greater than zero.

Original entry on oeis.org

1, 4, 5, 9, 12, 13, 17, 20, 21, 25, 28, 29, 65, 68, 69, 73, 76, 77, 81, 84, 85, 89, 92, 93, 129, 132, 133, 137, 140, 141, 145, 148, 149, 153, 156, 157, 193, 196, 197, 201, 204, 205, 209, 212, 213, 217, 220, 221, 256, 257, 260, 261, 264, 265, 268, 269, 272, 273
Offset: 1

Views

Author

Antti Karttunen, Dec 18 2006

Keywords

Comments

In these games, the left can always win.

Crossrefs

Intersection of complement of A126002 and A126001. Cf. A125991, A126001-A126003.
Showing 1-6 of 6 results.