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 1-4 of 4 results.

A277736 Positions of 0's in A277735.

Original entry on oeis.org

1, 4, 5, 6, 8, 10, 13, 14, 17, 18, 21, 22, 23, 25, 28, 29, 30, 32, 35, 36, 37, 39, 41, 44, 45, 48, 49, 50, 52, 54, 57, 58, 61, 62, 63, 65, 67, 70, 71, 74, 75, 78, 79, 80, 82, 85, 86, 87, 89, 91, 94, 95, 98, 99, 102, 103, 104, 106, 109, 110, 111, 113, 115, 118, 119, 122, 123, 126, 127, 128, 130, 133, 134
Offset: 1

Views

Author

N. J. A. Sloane, Nov 07 2016

Keywords

Comments

{A277736, A277737, A277738} forms a three-way partition of the positive integers, similar to {A003144, A003145, A003146}.

Crossrefs

Programs

  • Maple
    with(ListTools);
    T:=proc(S) Flatten(subs( {0=[0,1], 1=[2,0], 2=[0]}, S)); end;
    S:=[0];
    for n from 1 to 14 do S:=T(S); od:
    S; # A277735
    p0:=[]: p1:=[]: p2:=[]:
    for i from 1 to nops(S) do
    j:=S[i];
    if j=0 then p0:=[op(p0),i];
    elif j=1 then p1:=[op(p1),i];
    else p2:=[op(p2),i]; fi: od:
    p0; # A277736
    p1; # A277737
    p2: # A277738

A277737 Positions of 1's in A277735.

Original entry on oeis.org

2, 7, 9, 11, 15, 19, 24, 26, 31, 33, 38, 40, 42, 46, 51, 53, 55, 59, 64, 66, 68, 72, 76, 81, 83, 88, 90, 92, 96, 100, 105, 107, 112, 114, 116, 120, 124, 129, 131, 136, 138, 143, 145, 147, 151, 156, 158, 160, 164, 168, 173, 175, 180, 182, 187, 189, 191, 195, 200, 202, 204, 208, 212, 217, 219, 224, 226
Offset: 1

Views

Author

N. J. A. Sloane, Nov 07 2016

Keywords

Comments

{A277736, A277737, A277738} forms a three-way partition of the positive integers, similar to {A003144, A003145, A003146}.

Crossrefs

Programs

  • Maple
    with(ListTools);
    T:=proc(S) Flatten(subs( {0=[0,1], 1=[2,0], 2=[0]}, S)); end;
    S:=[0];
    for n from 1 to 14 do S:=T(S); od:
    S; # A277735
    p0:=[]: p1:=[]: p2:=[]:
    for i from 1 to nops(S) do
    j:=S[i];
    if j=0 then p0:=[op(p0),i];
    elif j=1 then p1:=[op(p1),i];
    else p2:=[op(p2),i]; fi: od:
    p0; # A277736
    p1; # A277737
    p2: # A277738

A277738 Positions of 2's in A277735.

Original entry on oeis.org

3, 12, 16, 20, 27, 34, 43, 47, 56, 60, 69, 73, 77, 84, 93, 97, 101, 108, 117, 121, 125, 132, 139, 148, 152, 161, 165, 169, 176, 183, 192, 196, 205, 209, 213, 220, 227, 236, 240, 249, 253, 262, 266, 270, 277, 286, 290, 294, 301, 308, 317, 321, 330, 334, 343, 347, 351, 358, 367, 371, 375, 382, 389, 398
Offset: 1

Views

Author

N. J. A. Sloane, Nov 07 2016

Keywords

Comments

{A277736, A277737, A277738} forms a three-way partition of the positive integers, similar to {A003144, A003145, A003146}.

Crossrefs

Programs

  • Maple
    with(ListTools);
    T:=proc(S) Flatten(subs( {0=[0,1], 1=[2,0], 2=[0]}, S)); end;
    S:=[0];
    for n from 1 to 14 do S:=T(S); od:
    S; # A277735
    p0:=[]: p1:=[]: p2:=[]:
    for i from 1 to nops(S) do
    j:=S[i];
    if j=0 then p0:=[op(p0),i];
    elif j=1 then p1:=[op(p1),i];
    else p2:=[op(p2),i]; fi: od:
    p0; # A277736
    p1; # A277737
    p2: # A277738

A317953 Apply the morphism 1 -> {1, 2}, 2 -> {3,1}, 3 -> {1} n times to 1, and concatenate the resulting string.

Original entry on oeis.org

1, 12, 1231, 1231112, 1231112121231, 123111212123112311231112, 12311121212311231123111212311121231112121231, 123111212123112311231112123111212311121212311231112121231123111212123112311231112
Offset: 1

Views

Author

N. J. A. Sloane, Aug 21 2018

Keywords

Comments

For the tribonacci word A092782, each block b(n) (see A103269) is the concatenation of the three previous blocks: b(n) = b(n-1).b(n-2).b(n-3). Instead, here we have a(n) = a(n-1).a(n-3).a(n-2), as can be seen in the examples section below.

Examples

			a(1): 1,
a(2): 12,
a(3): 1231,
a(4): 1231112,
a(5): 1231112121231,
a(6): 123111212123112311231112,
a(7): 12311121212311231123111212311121231112121231,
equals a(6).a(4).a(5), look:
a(6):123111212123112311231112,
a(4):                        1231112,
a(5):                               1231112121231,
a(8): 123111212123112311231112123111212311121212311231112121231123111212123112311231112
equals a(7).a(5).a(6), look:
a(7): 12311121212311231123111212311121231112121231,
a(5):                                             1231112121231,
a(6):                                                          123111212123112311231112,
		

References

  • V. F. Sirvent, Semigroups and the self-similar structure of the flipped tribonacci substitution, Applied Math. Letters, 12 (1999), 25-29.

Crossrefs

Cf. A100619 (the limiting string), A277735, A317953.
A103269 is the analog for the word A092782.
Showing 1-4 of 4 results.