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 1-5 of 5 results.

A327973 Bitwise XOR of two successive generations (centrally aligned) in the trajectory of rule 30 started from a lone 1 cell: a(n) = A110240(n) XOR 2*A110240(n-1).

Original entry on oeis.org

5, 23, 93, 335, 1493, 5351, 23853, 85951, 382405, 1369943, 6103965, 21996687, 97906325, 350709671, 1562619373, 5631262591, 25064000389, 89782414999, 400033474525, 1441615751887, 6416397448021, 22984338788455, 102408232210605, 369052763468095, 1642598765228869, 5883986891577303, 26216498605021469, 94477513773305103
Offset: 1

Views

Author

Antti Karttunen, Oct 03 2019

Keywords

Crossrefs

Cf. A110240, A269160, A327974 (gives the middle bit), A328107 (binary weight of terms).
Cf. also A327971, A327972, A327976, A328103, A328104 for other such combinations.

Programs

Formula

a(n) = A110240(n) XOR 2*A110240(n-1).

A328106 Binary weight of A327971: a(n) = A000120(A110240(n) XOR A030101(A110240(n))).

Original entry on oeis.org

0, 0, 2, 2, 2, 4, 6, 4, 8, 10, 10, 8, 12, 8, 18, 6, 12, 26, 16, 18, 14, 18, 20, 22, 22, 26, 26, 38, 30, 26, 36, 26, 28, 36, 28, 18, 28, 42, 36, 32, 34, 40, 44, 38, 40, 50, 48, 48, 50, 58, 46, 56, 48, 42, 54, 48, 56, 56, 46, 54, 48, 52, 60, 58, 78, 74, 64, 60, 66, 74, 74, 64, 80, 74, 80, 62, 92, 62, 80, 70, 68, 100, 90, 82, 80, 92
Offset: 0

Views

Author

Antti Karttunen, Oct 05 2019

Keywords

Comments

a(n) is the number of times the k-th cell from the left is different from the k-th cell from the right, at the generation n of Rule 30 1-D cellular automaton, when it is started from a single alive cell.
All terms are even.

Examples

			The evolution of one-dimensional cellular automaton rule 30 proceeds as follows, when started from a single alive (1) cell:
---------------------------------------------- a(n)
   0:              (1)                          0
   1:             1(1)1                         0
   2:            11(0)01                        2
   3:           110(1)111                       2
   4:          1100(1)0001                      2
   5:         11011(1)10111                     4
   6:        110010(0)001001                    6
   7:       1101111(0)0111111                   4
   8:      11001000(1)11000001                  8
   9:     110111101(1)001000111                10
  10:    1100100001(0)1111011001               10
  11:   11011110011(0)10000101111               8
  12:  110010001110(0)110011010001             12
  13: 1101111011001(1)1011100110111             8
When we count the times the k-th cell from the left is different from the k-th cell from the right, we obtain a(n). Note that the central cells (indicated with parentheses) do not affect the count, as the central cell is always equal to itself.
		

Crossrefs

Programs

Formula

a(n) = Sum_{i=0..2n} abs(A070950(n,i)-A070950(n,n-i)).

A328105 Binary weight of A328104: a(n) = A000120(A110240(n) OR 2*A110240(n)).

Original entry on oeis.org

2, 4, 5, 8, 7, 12, 9, 15, 11, 17, 17, 20, 19, 26, 21, 29, 22, 27, 30, 33, 30, 34, 37, 40, 37, 39, 41, 49, 44, 49, 48, 53, 41, 56, 49, 64, 50, 62, 59, 66, 64, 60, 66, 69, 61, 77, 65, 73, 67, 74, 70, 89, 78, 87, 78, 94, 85, 88, 89, 100, 91, 101, 95, 110, 92, 85, 98, 102, 102, 102, 115, 109, 101, 105, 121, 118, 121, 129
Offset: 0

Views

Author

Antti Karttunen, Oct 05 2019

Keywords

Crossrefs

Programs

Formula

For all n >= 0, A070952(a) < a(n) <= 2*A070952(n).

A328108 Binary weight of A327976.

Original entry on oeis.org

2, 4, 3, 6, 5, 12, 7, 11, 9, 13, 7, 12, 13, 20, 15, 23, 16, 19, 22, 25, 20, 28, 19, 30, 29, 39, 27, 29, 32, 37, 32, 37, 29, 38, 37, 38, 36, 44, 47, 44, 42, 46, 42, 53, 41, 49, 53, 47, 45, 58, 52, 55, 56, 65, 66, 60, 67, 56, 61, 64, 63, 77, 59, 66, 60, 67, 72, 72, 64, 84, 57, 81, 63, 79, 67, 92, 77, 77, 74, 80, 81, 88, 77
Offset: 1

Views

Author

Antti Karttunen, Oct 05 2019

Keywords

Crossrefs

Programs

Formula

a(n) = A000120(A327976(n)).
a(n) = A000120(A110240(n) XOR 2*A265281(n-1)).
a(n) = A000120(A110240(n) XOR 2*A030101(A110240(n-1))).

A328109 Binary weight of A328103: a(n) = A000120(A110240(n) XOR A267357(n)).

Original entry on oeis.org

0, 1, 4, 3, 5, 6, 8, 10, 9, 11, 11, 14, 14, 13, 16, 11, 18, 16, 17, 25, 18, 21, 25, 24, 22, 30, 25, 28, 30, 26, 33, 34, 36, 34, 33, 37, 37, 44, 38, 44, 51, 38, 43, 48, 45, 57, 38, 47, 50, 52, 49, 61, 53, 56, 63, 58, 56, 54, 60, 59, 64, 54, 60, 66, 69, 60, 67, 69, 72, 68, 75, 74, 77, 68, 78, 76, 75, 78, 72, 81, 80, 91, 78
Offset: 0

Views

Author

Antti Karttunen, Oct 05 2019

Keywords

Crossrefs

Programs

Formula

a(n) = A000120(A328103(n)) = A000120(A110240(n) XOR A267357(n)).
Showing 1-5 of 5 results.