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 18 results. Next

A006042 The nim-square of n.

Original entry on oeis.org

0, 1, 3, 2, 6, 7, 5, 4, 13, 12, 14, 15, 11, 10, 8, 9, 24, 25, 27, 26, 30, 31, 29, 28, 21, 20, 22, 23, 19, 18, 16, 17, 52, 53, 55, 54, 50, 51, 49, 48, 57, 56, 58, 59, 63, 62, 60, 61, 44, 45, 47, 46, 42, 43, 41, 40, 33, 32, 34, 35, 39, 38, 36, 37, 103, 102, 100, 101, 97, 96, 98, 99
Offset: 0

Views

Author

Keywords

Comments

This is a permutation of the natural numbers; A160679 is the inverse permutation. - Jianing Song, Aug 10 2022

References

  • J. H. Conway, On Numbers and Games. Academic Press, NY, 1976, pp. 51-53.
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Diagonal of A051775. Without 0, diagonal of A051776.
Column 2 of array in A335162.
Other nim k-th powers: A051917 (k=-1), A160679 (k=1/2), A335170 (k=3), A335535 (k=4), A335171 (k=5), A335172 (k=6), A335173 (k=7), A335536 (k=8).

Programs

Formula

a(n) = A051775(n,n).
From Jianing Song, Aug 10 2022: (Start)
If n = Sum_j 2^e(j), then a(n) is the XOR of A006017(e(j))'s. Proof: let N+ = XOR and N* denote the nim addition and the nim multiplication, then n N* n = (Sum_j 2^e(j)) N* (Sum_j 2^e(j)) = (Nim-sum_j 2^e(j)) N* (Nim-sum_j 2^e(j)) = (Nim-sum_j (2^e(j) N* 2^e(j))) N+ (Nim-sum_{i
For example, for n = 11 = 2^0 + 2^1 + 2^3, a(11) = A006017(0) XOR A006017(1) XOR A006017(3) = 1 XOR 3 XOR 13 = 15.
More generally, if n = Sum_j 2^e(j), k is a power of 2, then the nim k-th power of n is the XOR of (nim k-th power of 2^e(j))'s. (End)

Extensions

a(1)-a(49) confirmed, a(50)-a(71) added by John W. Layman, Nov 05 2010
a(0) prepended by Jianing Song, Aug 10 2022

A335170 Nim-cube of n.

Original entry on oeis.org

0, 1, 1, 1, 14, 13, 8, 10, 14, 10, 13, 8, 14, 8, 10, 13, 152, 145, 133, 141, 189, 182, 167, 173, 203, 199, 212, 217, 224, 238, 248, 247, 152, 141, 145, 133, 224, 247, 238, 248, 189, 173, 182, 167, 203, 217, 199, 212, 152, 133, 141, 145, 203, 212, 217, 199, 224
Offset: 0

Author

N. J. A. Sloane, Jun 12 2020

Keywords

Crossrefs

A column of the array in A335162.

Programs

  • PARI
    \\ See Links section.

Extensions

More terms from Rémy Sigrist, Jun 12 2020

A335172 Nim sixth-power of n.

Original entry on oeis.org

0, 1, 1, 1, 8, 10, 13, 14, 8, 14, 10, 13, 8, 13, 14, 10, 203, 199, 217, 212, 248, 247, 238, 224, 182, 189, 167, 173, 141, 133, 152, 145, 203, 212, 199, 217, 141, 145, 133, 152, 248, 224, 247, 238, 182, 173, 189, 167, 203, 217, 212, 199, 182, 167, 173, 189, 141
Offset: 0

Author

N. J. A. Sloane, Jun 12 2020

Keywords

Crossrefs

A column of the array in A335162.

Extensions

More terms from Rémy Sigrist, Jun 12 2020

A335171 Nim fifth-power of n.

Original entry on oeis.org

0, 1, 3, 2, 2, 2, 3, 3, 1, 2, 1, 2, 3, 1, 1, 3, 72, 76, 65, 69, 88, 93, 83, 86, 106, 108, 96, 102, 122, 125, 114, 117, 196, 207, 200, 195, 229, 239, 235, 225, 244, 253, 251, 242, 213, 221, 216, 208, 140, 130, 138, 132, 191, 176, 187, 180, 159, 147, 154, 150
Offset: 0

Author

N. J. A. Sloane, Jun 12 2020

Keywords

Crossrefs

A column of the array in A335162.

Extensions

More terms from Rémy Sigrist, Jun 12 2020

A335173 Nim seventh-power of n.

Original entry on oeis.org

0, 1, 2, 3, 11, 9, 15, 12, 13, 4, 14, 5, 6, 10, 8, 7, 118, 113, 32, 34, 105, 111, 40, 42, 78, 74, 55, 52, 58, 57, 95, 90, 155, 51, 146, 48, 31, 175, 30, 165, 190, 63, 181, 60, 135, 24, 143, 25, 237, 16, 17, 227, 201, 46, 44, 197, 37, 250, 245, 39, 215, 20, 21
Offset: 0

Author

N. J. A. Sloane, Jun 12 2020

Keywords

Crossrefs

A column of the array in A335162.

Extensions

More terms from Rémy Sigrist, Jun 12 2020

A335535 Nim fourth-power of n.

Original entry on oeis.org

0, 1, 2, 3, 5, 4, 7, 6, 10, 11, 8, 9, 15, 14, 13, 12, 21, 20, 23, 22, 16, 17, 18, 19, 31, 30, 29, 28, 26, 27, 24, 25, 42, 43, 40, 41, 47, 46, 45, 44, 32, 33, 34, 35, 37, 36, 39, 38, 63, 62, 61, 60, 58, 59, 56, 57, 53, 52, 55, 54, 48, 49, 50, 51, 87, 86, 85, 84
Offset: 0

Author

Rémy Sigrist, Jun 13 2020

Keywords

Crossrefs

A column of the array in A335162.

A335536 Nim eighth-power of n.

Original entry on oeis.org

0, 1, 3, 2, 7, 6, 4, 5, 14, 15, 13, 12, 9, 8, 10, 11, 31, 30, 28, 29, 24, 25, 27, 26, 17, 16, 18, 19, 22, 23, 21, 20, 58, 59, 57, 56, 61, 60, 62, 63, 52, 53, 55, 54, 51, 50, 48, 49, 37, 36, 38, 39, 34, 35, 33, 32, 43, 42, 40, 41, 44, 45, 47, 46, 123, 122, 120
Offset: 0

Author

Rémy Sigrist, Jun 13 2020

Keywords

Crossrefs

A column of the array in A335162.

A059971 n^n using Nim multiplication.

Original entry on oeis.org

1, 1, 3, 1, 5, 2, 13, 12, 14, 13, 1, 6, 13, 8, 13, 1, 17, 8, 158, 155, 72, 170, 198, 48, 145, 208, 165, 25, 55, 205, 171, 206, 55, 158, 6, 140, 151, 53, 113, 252, 191, 254, 228, 26, 116, 130, 146, 243, 145, 118, 72, 14, 75, 115, 20, 69, 60, 177, 121, 99, 171, 169, 170
Offset: 0

Author

John W. Layman, Mar 05 2001

Keywords

Crossrefs

Programs

  • PARI
    See Links section.

Formula

a(n) = A335162(n, n). - Rémy Sigrist, Jun 12 2020

Extensions

a(0) = 1 prepended by Rémy Sigrist, Jun 12 2020

A160679 Square root of n under Nim (or Conway) multiplication.

Original entry on oeis.org

0, 1, 3, 2, 7, 6, 4, 5, 14, 15, 13, 12, 9, 8, 10, 11, 30, 31, 29, 28, 25, 24, 26, 27, 16, 17, 19, 18, 23, 22, 20, 21, 57, 56, 58, 59, 62, 63, 61, 60, 55, 54, 52, 53, 48, 49, 51, 50, 39, 38, 36, 37, 32, 33, 35, 34, 41, 40, 42, 43, 46, 47, 45, 44, 124, 125, 127, 126, 123, 122, 120
Offset: 0

Author

Gerard P. Michon, Jun 25 2009

Keywords

Comments

Because Conway's field On2 (endowed with Nim-multiplication and [bitwise] Nim-addition) has characteristic 2, the Nim-square function (A006042) is an injective field homomorphism (i.e., the square of a sum is the sum of the squares). Thus the square function is a bijection within any finite additive subgroup of On2 (which is a fancy way to say that an integer and its Nim-square have the same bit length). Therefore the Nim square-root function is also a field homomorphism (the square-root of a Nim-sum is the Nim-sum of the square roots) which can be defined as the inverse permutation of A006042 (as such, it preserves bit-length too).

Examples

			a(2) = 3 because TIM(3,3) = 2
More generally, a(x)=y because A006042(y)=x.
		

Crossrefs

Cf. A006042 (Nim-squares). A051917 (Nim-reciprocals), A335162, A212200.

Formula

Letting NIM (= XOR) TIM and RIM denote respectively the sum, product and square root in Conway's Nim-field On2, we see that the bit-length of NIM(x,TIM(x,x)) is less than that of the positive integer x. This remark turns the following relations into an effective recursive definition of a(n) = RIM(n) which uses the fact that RIM is a field homomorphism in On2:
a(0) = 0
a(n) = NIM(n, a(NIM(n, a(n, TIM(n,n)) )
Note: TIM(n,n) = A006042(n)
From Jianing Song, Aug 10 2022: (Start)
For 0 <= n <= 2^2^k-1, a(n) = A335162(n, 2^(2^k-1)). This is because {0,1,...,2^2^k-1} together with the nim operations makes a field isomorphic to GF(2^2^k).
Also for n > 0, a(n) = A335162(n, (A212200(n)+1)/2). (End)

A333862 a(n) is the greatest nim-power of n.

Original entry on oeis.org

1, 1, 3, 3, 15, 15, 15, 15, 14, 15, 14, 15, 15, 14, 14, 15, 252, 252, 255, 255, 252, 252, 255, 255, 252, 252, 255, 255, 255, 255, 252, 252, 255, 255, 255, 255, 252, 255, 252, 255, 255, 255, 255, 255, 255, 252, 255, 252, 255, 252, 252, 255, 255, 255, 255, 255
Offset: 0

Author

Rémy Sigrist, Jun 13 2020

Keywords

Comments

For any n >= 0, a(n) is the greatest term in n-th row of A335162.

Examples

			For n = 10:
- the first nim-powers of 10 are: 1, 10, 14, 13, 8, 1, ...
- so a(10) = 14.
		

Crossrefs

Cf. A335162.

Programs

  • C
    See Links section.
Showing 1-10 of 18 results. Next