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

A268820 Square array A(r,c): A(0,c) = c, A(r,0) = 0, A(r>=1,c>=1) = A003188(1+A006068(A(r-1,c-1))) = A268717(1+A(r-1,c-1)), read by descending antidiagonals as A(0,0), A(0,1), A(1,0), A(0,2), A(1,1), A(2,0), ...

Original entry on oeis.org

0, 1, 0, 2, 1, 0, 3, 3, 1, 0, 4, 6, 3, 1, 0, 5, 2, 2, 3, 1, 0, 6, 12, 7, 2, 3, 1, 0, 7, 4, 6, 6, 2, 3, 1, 0, 8, 7, 13, 5, 6, 2, 3, 1, 0, 9, 5, 12, 7, 7, 6, 2, 3, 1, 0, 10, 24, 5, 15, 4, 7, 6, 2, 3, 1, 0, 11, 8, 4, 13, 5, 5, 7, 6, 2, 3, 1, 0, 12, 11, 25, 4, 14, 12, 5, 7, 6, 2, 3, 1, 0, 13, 9, 24, 12, 15, 4, 4, 5, 7, 6, 2, 3, 1, 0, 14, 13, 9, 27, 12, 10, 13, 4, 5, 7, 6, 2, 3, 1, 0
Offset: 0

Views

Author

Antti Karttunen, Feb 14 2016

Keywords

Examples

			The top left [0 .. 16] x [0 .. 19] section of the array:
0, 1, 2, 3, 4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19
0, 1, 3, 6, 2, 12,  4,  7,  5, 24,  8, 11,  9, 13, 15, 10, 14, 48, 16, 19
0, 1, 3, 2, 7,  6, 13, 12,  5,  4, 25, 24,  9,  8, 15, 14, 11, 10, 49, 48
0, 1, 3, 2, 6,  5,  7, 15, 13,  4, 12, 27, 25,  8, 24, 14, 10,  9, 11, 51
0, 1, 3, 2, 6,  7,  4,  5, 14, 15, 12, 13, 26, 27, 24, 25, 10, 11,  8,  9
0, 1, 3, 2, 6,  7,  5, 12,  4, 10, 14, 13, 15, 30, 26, 25, 27, 11,  9, 24
0, 1, 3, 2, 6,  7,  5,  4, 13, 12, 11, 10, 15, 14, 31, 30, 27, 26,  9,  8
0, 1, 3, 2, 6,  7,  5,  4, 12, 15, 13,  9, 11, 14, 10, 29, 31, 26, 30,  8
0, 1, 3, 2, 6,  7,  5,  4, 12, 13, 14, 15,  8,  9, 10, 11, 28, 29, 30, 31
0, 1, 3, 2, 6,  7,  5,  4, 12, 13, 15, 10, 14, 24,  8, 11,  9, 20, 28, 31
0, 1, 3, 2, 6,  7,  5,  4, 12, 13, 15, 14, 11, 10, 25, 24,  9,  8, 21, 20
0, 1, 3, 2, 6,  7,  5,  4, 12, 13, 15, 14, 10,  9, 11, 27, 25,  8, 24, 23
0, 1, 3, 2, 6,  7,  5,  4, 12, 13, 15, 14, 10, 11,  8,  9, 26, 27, 24, 25
0, 1, 3, 2, 6,  7,  5,  4, 12, 13, 15, 14, 10, 11,  9, 24,  8, 30, 26, 25
0, 1, 3, 2, 6,  7,  5,  4, 12, 13, 15, 14, 10, 11,  9,  8, 25, 24, 31, 30
0, 1, 3, 2, 6,  7,  5,  4, 12, 13, 15, 14, 10, 11,  9,  8, 24, 27, 25, 29
0, 1, 3, 2, 6,  7,  5,  4, 12, 13, 15, 14, 10, 11,  9,  8, 24, 25, 26, 27
		

Crossrefs

Inverses of these permutations can be found in table A268830.
Row 0: A001477, Row 1: A268717, Row 2: A268821, Row 3: A268823, Row 4: A268825, Row 5: A268827, Row 6: A268831, Row 7: A268933.
Rows converge towards A003188, which is also the main diagonal.
Cf. array A268715 (can be extracted from this one).
Cf. array A268833 (shows related Hamming distances with regular patterns).

Programs

  • Mathematica
    A003188[n_]:=BitXor[n, Floor[n/2]]; A006068[n_]:=If[n<2, n, Block[{m=A006068[Floor[n/2]]}, 2m + Mod[Mod[n,2] + Mod[m, 2], 2]]]; a[r_, 0]:= 0; a[0, c_]:=c; a[r_, c_]:= A003188[1 + A006068[a[r - 1, c - 1]]]; Table[a[c, r - c], {r, 0, 15}, {c, 0, r}] //Flatten (* Indranil Ghosh, Apr 02 2017 *)
  • PARI
    A003188(n) = bitxor(n, n\2);
    A006068(n) = if(n<2, n, {my(m = A006068(n\2)); 2*m + (n%2 + m%2)%2});
    a(r, c) = if(r==0, c, if(c==0, 0, A003188(1 + A006068(a(r - 1, c - 1)))));
    for(r=0, 15, for(c=0, r, print1(a(c, r - c),", "); ); print(); ); \\ Indranil Ghosh, Apr 02 2017
    
  • Python
    def A003188(n): return n^(n//2)
    def A006068(n):
        if n<2: return n
        else:
            m=A006068(n//2)
            return 2*m + (n%2 + m%2)%2
    def a(r, c): return c if r<1 else 0 if c<1 else A003188(1 + A006068(a(r - 1, c - 1)))
    for r in range(16):
        print([a(c, r - c) for c in range(r + 1)]) # Indranil Ghosh, Apr 02 2017
  • Scheme
    (define (A268820 n) (A268820bi (A002262 n) (A025581 n)))
    (define (A268820bi row col) (cond ((zero? row) col) ((zero? col) 0) (else (A268717 (+ 1 (A268820bi (- row 1) (- col 1)))))))
    (define (A268820bi row col) (cond ((zero? row) col) ((zero? col) 0) (else (A003188 (+ 1 (A006068 (A268820bi (- row 1) (- col 1))))))))
    

Formula

For row zero: A(0,k) = k, for column zero: A(n,0) = 0, and in other cases: A(n,k) = A003188(1+A006068(A(n-1,k-1)))
Other identities. For all n >= 0:
A(n,n) = A003188(n).
A(A006068(n),A006068(n)) = n.

A268823 Permutation of nonnegative integers: a(0) = 0, a(n) = A268717(1 + A268821(n-1)).

Original entry on oeis.org

0, 1, 3, 2, 6, 5, 7, 15, 13, 4, 12, 27, 25, 8, 24, 14, 10, 9, 11, 51, 49, 16, 48, 22, 18, 17, 19, 26, 30, 29, 31, 23, 21, 28, 20, 99, 97, 32, 96, 38, 34, 33, 35, 42, 46, 45, 47, 39, 37, 44, 36, 50, 54, 53, 55, 63, 61, 52, 60, 43, 41, 56, 40, 62, 58, 57, 59, 195, 193, 64, 192, 70, 66, 65, 67, 74, 78, 77, 79, 71, 69, 76, 68, 82, 86, 85
Offset: 0

Views

Author

Antti Karttunen, Feb 14 2016

Keywords

Comments

The "third shifted power" of permutation A268717.

Crossrefs

Inverse: A268824.
Row 3 of array A268820.

Programs

Formula

a(0), for n >= 1, a(n) = A268717(1 + A268821(n-1)).
a(0) = 0, a(1) = 1, and for n > 1, a(n) = A268717(1 + A268717(1 + A268717(n-2))).
For n >= 3, a(n) = A003188(3+A006068(n-3)). - Antti Karttunen, Mar 11 2024

A268825 Permutation of nonnegative integers: a(0) = 0, a(n) = A268717(1+A268823(n-1)).

Original entry on oeis.org

0, 1, 3, 2, 6, 7, 4, 5, 14, 15, 12, 13, 26, 27, 24, 25, 10, 11, 8, 9, 50, 51, 48, 49, 18, 19, 16, 17, 30, 31, 28, 29, 22, 23, 20, 21, 98, 99, 96, 97, 34, 35, 32, 33, 46, 47, 44, 45, 38, 39, 36, 37, 54, 55, 52, 53, 62, 63, 60, 61, 42, 43, 40, 41, 58, 59, 56, 57, 194, 195, 192, 193, 66, 67, 64, 65, 78, 79, 76, 77, 70, 71, 68, 69, 86, 87
Offset: 0

Views

Author

Antti Karttunen, Feb 14 2016

Keywords

Comments

The "fourth shifted power" of permutation A268717.

Crossrefs

Inverse: A268826.
Row 4 of array A268820.

Programs

Formula

a(0) = 0, and for n >= 1, a(n) = A268717(1+A268823(n-1)).

A268821 Permutation of nonnegative integers: a(0) = 0, a(n) = A268717(1 + A268717(n-1)).

Original entry on oeis.org

0, 1, 3, 2, 7, 6, 13, 12, 5, 4, 25, 24, 9, 8, 15, 14, 11, 10, 49, 48, 17, 16, 23, 22, 19, 18, 27, 26, 31, 30, 21, 20, 29, 28, 97, 96, 33, 32, 39, 38, 35, 34, 43, 42, 47, 46, 37, 36, 45, 44, 51, 50, 55, 54, 61, 60, 53, 52, 41, 40, 57, 56, 63, 62, 59, 58, 193, 192, 65, 64, 71, 70, 67, 66, 75, 74, 79, 78, 69, 68, 77, 76, 83, 82
Offset: 0

Views

Author

Antti Karttunen, Feb 14 2016

Keywords

Comments

The "shifted square" of permutation A268717.

Crossrefs

Inverse: A268822.
Row 2 of array A268820.
From term a(2) onward (3, 2, 7, 6, ...) also row 3 of A268715.
Cf. also A101080, A268833.

Programs

Formula

a(0) = 0, for n >= 1, a(n) = A268717(1 + A268717(n-1)).
Other identities. For all n >= 0:
A101080(n, a(n+2)) = 2.

A268827 Permutation of nonnegative integers: a(0) = 0, a(n) = A268717(1+A268825(n-1)).

Original entry on oeis.org

0, 1, 3, 2, 6, 7, 5, 12, 4, 10, 14, 13, 15, 30, 26, 25, 27, 11, 9, 24, 8, 54, 50, 49, 51, 19, 17, 48, 16, 31, 29, 20, 28, 18, 22, 21, 23, 102, 98, 97, 99, 35, 33, 96, 32, 47, 45, 36, 44, 34, 38, 37, 39, 55, 53, 60, 52, 58, 62, 61, 63, 46, 42, 41, 43, 59, 57, 40, 56, 198, 194, 193, 195, 67, 65, 192, 64, 79, 77, 68, 76, 66, 70, 69, 71, 87
Offset: 0

Views

Author

Antti Karttunen, Feb 14 2016

Keywords

Comments

The "fifth shifted power" of permutation A268717.

Crossrefs

Inverse: A268828.
Row 5 of array A268820.

Programs

Formula

a(0) = 0, for n >= 1, a(n) = A268717(1+A268825(n-1)).

A268831 Permutation of nonnegative integers: a(0) = 0, a(n) = A268717(1+A268827(n-1)).

Original entry on oeis.org

0, 1, 3, 2, 6, 7, 5, 4, 13, 12, 11, 10, 15, 14, 31, 30, 27, 26, 9, 8, 25, 24, 55, 54, 51, 50, 17, 16, 49, 48, 29, 28, 21, 20, 19, 18, 23, 22, 103, 102, 99, 98, 33, 32, 97, 96, 45, 44, 37, 36, 35, 34, 39, 38, 53, 52, 61, 60, 59, 58, 63, 62, 47, 46, 43, 42, 57, 56, 41, 40, 199, 198, 195, 194, 65, 64, 193, 192, 77
Offset: 0

Views

Author

Antti Karttunen, Feb 14 2016

Keywords

Comments

The sixth "shifted power" of A268717.

Crossrefs

Inverse: A268832.
Row 6 of A268820.

Programs

Formula

a(0) = 0, for n >= 1, a(n) = A268717(1+A268827(n-1)).

A268726 Index of the toggled bit between n and A268717(n+1): a(n) = A000523(A003987(n, A268717(1+n))).

Original entry on oeis.org

0, 1, 2, 0, 3, 0, 0, 1, 4, 0, 0, 1, 0, 1, 2, 0, 5, 0, 0, 1, 0, 1, 2, 0, 0, 1, 2, 0, 3, 0, 0, 1, 6, 0, 0, 1, 0, 1, 2, 0, 0, 1, 2, 0, 3, 0, 0, 1, 0, 1, 2, 0, 3, 0, 0, 1, 4, 0, 0, 1, 0, 1, 2, 0, 7, 0, 0, 1, 0, 1, 2, 0, 0, 1, 2, 0, 3, 0, 0, 1, 0, 1, 2, 0, 3, 0, 0, 1, 4, 0, 0, 1, 0, 1, 2, 0, 0, 1, 2, 0, 3, 0, 0, 1, 4, 0, 0, 1, 0, 1, 2, 0, 5, 0, 0, 1, 0, 1, 2, 0, 0
Offset: 0

Views

Author

Antti Karttunen, Feb 13 2016

Keywords

Comments

A fractal sequence, because a permutation of A007814. Removing zeros yields A268727(n) = a(n)+1.

Crossrefs

One less than A268727.
Cf. also array A268833.

Programs

Formula

a(n) = A007814(1 + A006068(n)).
a(n) = A000523(A003987(n, A268717(1+n))).
a(n) = floor(log_2(n XOR A003188(1 + A006068(n)))).
Other identities:
For all n >= 1, a(A003188(n-1)) = A007814(n).

A268727 One-based index of the toggled bit between n and A268717(n+1): a(n) = A070939(A003987(n,A268717(1+n))).

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Feb 13 2016

Keywords

Comments

A fractal sequence like A268726.

Crossrefs

One more than A268726.
Cf. also array A268833.

Programs

Formula

a(n) = A001511(1+A006068(n)).
a(n) = A070939(A003987(n,A268717(1+n))).
a(n) = 1 + floor(log_2(n XOR A003188(1+A006068(n)))).
a(n) = A001511(n)*(1-A010059(n)) + 1. - Alan Michael Gómez Calderón, Jun 15 2025

A268817 Permutation of nonnegative integers: a(n) = A268717(A268717(n)).

Original entry on oeis.org

0, 1, 6, 4, 3, 9, 2, 7, 12, 22, 5, 11, 24, 13, 10, 8, 15, 45, 14, 19, 48, 21, 18, 16, 23, 25, 30, 28, 27, 17, 26, 31, 20, 94, 29, 35, 96, 37, 34, 32, 39, 41, 46, 44, 43, 33, 42, 47, 36, 49, 54, 52, 51, 57, 50, 55, 60, 38, 53, 59, 40, 61, 58, 56, 63, 189, 62, 67, 192, 69, 66, 64, 71, 73, 78, 76, 75, 65, 74, 79, 68, 81
Offset: 0

Views

Author

Antti Karttunen, Feb 14 2016

Keywords

Crossrefs

Inverse: A268818.
Cf. A268717.
Cf. also A268821.

Programs

Formula

a(n) = A268717(A268717(n)).

A268933 Permutation of nonnegative integers: a(0) = 0, for n >= 1, a(n) = A268717(1 + A268831(n-1)).

Original entry on oeis.org

0, 1, 3, 2, 6, 7, 5, 4, 12, 15, 13, 9, 11, 14, 10, 29, 31, 26, 30, 8, 24, 27, 25, 53, 55, 50, 54, 16, 48, 51, 49, 28, 20, 23, 21, 17, 19, 22, 18, 101, 103, 98, 102, 32, 96, 99, 97, 44, 36, 39, 37, 33, 35, 38, 34, 52, 60, 63, 61, 57, 59, 62, 58, 45, 47, 42, 46, 56, 40, 43, 41, 197, 199, 194, 198, 64, 192, 195, 193, 76
Offset: 0

Views

Author

Antti Karttunen, Feb 16 2016

Keywords

Comments

The seventh "shifted power" of A268717.

Crossrefs

Inverse: A268934.
Row 7 of A268820.
From term a(7) onward (4, 12, 15, 13, 9, 11, ...) also row 4 of A268715.

Programs

Formula

a(0) = 0, for n >= 1, a(n) = A268717(1 + A268831(n-1)).
Showing 1-10 of 18 results. Next