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.

A087483 Row 0 of the order array of 3/2, i.e., row 0 of the transposable dispersion in A087465.

Original entry on oeis.org

1, 2, 4, 6, 9, 13, 17, 22, 28, 34, 41, 49, 57, 66, 76, 86, 97, 109, 121, 134, 148, 162, 177, 193, 209, 226, 244, 262, 281, 301, 321, 342, 364, 386, 409, 433, 457, 482, 508, 534, 561, 589, 617, 646, 676, 706, 737, 769, 801, 834, 868, 902, 937, 973, 1009, 1046, 1084
Offset: 0

Views

Author

Clark Kimberling, Sep 09 2003

Keywords

Comments

Also, column 0 of the transposable dispersion in A087468.

Crossrefs

Programs

Formula

a(n) = n + 1 - floor(n/3) + Sum_{i=1..n} floor(2i/3).
a(n) = 1 + floor((n+1)^2/3) = 1 + A000212(n+1).
a(n) = A192735(n+2) / (n+2). - Reinhard Zumkeller, Jul 08 2011
G.f.: -(x^4-x^3+x^2+1) / ((x-1)^3*(x^2+x+1)). - Colin Barker, Mar 31 2013

Extensions

Edited by Max Alekseyev, Dec 05 2013

A087468 Dispersion, read by antidiagonals, of the complement of row 0 of the array R in A087465.

Original entry on oeis.org

1, 3, 2, 7, 5, 4, 12, 10, 8, 6, 19, 16, 14, 11, 9, 27, 24, 21, 18, 15, 13, 37, 33, 30, 26, 23, 20, 17, 48, 44, 40, 36, 32, 29, 25, 22, 61, 56, 52, 47, 43, 39, 35, 31, 28, 75, 70, 65, 60, 55, 51, 46, 42, 38, 34, 91, 85, 80, 74, 69, 64, 59, 54, 50, 45, 41, 108, 102, 96, 90, 84, 79
Offset: 0

Views

Author

Clark Kimberling, Sep 09 2003

Keywords

Comments

The sequence is a permutation of the natural numbers and the array is a transposable dispersion.

Examples

			Northwest corner of R:
1 ... 3 ... 7 ... 12 .. 19
2 ... 5 ... 10 .. 16 .. 24
4 ... 8 ... 14 .. 21 .. 30
6 ... 11 .. 18 .. 26 .. 36
9 ... 15 .. 23 .. 32 .. 43
(See example at A087465.)
		

Crossrefs

Cf. A087465.

Programs

  • Mathematica
    r = 20; r1 = 12;(*r=# rows of T,r1=# rows to show*);
    c = 20; c1 = 12;(*c=# cols of T,c1=# cols to show*);
    s[0] = 1; s[n_] := s[n] = s[n - 1] + 1 + Floor[3 n/2]; u = Table[s[n], {n, 0, 100}]
    v = Complement[Range[Max[u]], u]; f[n_] := v[[n]]; Table[f[n], {n, 1, 30}]
    mex[list_] := NestWhile[#1 + 1 &, 1, Union[list][[#1]] <= #1 &, 1,   Length[Union[list]]]; rows = {NestList[f, 1, c]}; Do[rows = Append[rows, NestList[f, mex[Flatten[rows]], r]], {r}]; w[i_, j_] := rows[[i, j]]; TableForm[Table[w[j, i], {i, 1, 10}, {j, 1, 10}]]   (*A087468 array*)
    Flatten[Table[w[n - k + 1, k], {n, 1, c1}, {k, 1, n}]] (*A087468 sequence*)
    TableForm[Table[w[j, 1] + w[1, i] + (i - 1)*(j - 1) - 1, {i, 1, 10}, {j, 1, 10}]] (*A087468 array,by formula*)

Formula

Transpose of the array R in A087465.

Extensions

Updated by Clark Kimberling, Sep 23 2014

A087466 a(n) = number of the row (counting from initial row 0) of the array R in A087465 that contains n.

Original entry on oeis.org

0, 0, 1, 0, 1, 0, 2, 1, 0, 2, 1, 3, 0, 2, 1, 3, 0, 2, 4, 1, 3, 0, 2, 4, 1, 3, 5, 0, 2, 4, 1, 3, 5, 0, 2, 4, 6, 1, 3, 5, 0, 2, 4, 6, 1, 3, 5, 7, 0, 2, 4, 6, 1, 3, 5, 7, 0, 2, 4, 6, 8, 1, 3, 5, 7, 0, 2, 4, 6, 8, 1, 3, 5, 7, 9, 0, 2, 4, 6, 8, 1, 3, 5, 7, 9, 0, 2, 4, 6, 8, 10, 1, 3, 5, 7, 9, 0, 2, 4, 6, 8, 10, 1, 3
Offset: 1

Views

Author

Clark Kimberling, Sep 09 2003

Keywords

Comments

A sequence that contains itself as a proper subsequence (infinitely many times); that is, a fractal sequence.

Examples

			Northwest corner of R:
1 2 4 6 9
3 5 8 11 15
7 10 14 18 23
12 16 21 26 32
19 24 30 36 43
a(10)=2 because 10 is in row 2.
		

Crossrefs

A087467 a(n) = number of the row (counting from initial row 1) of the array R in A087465 that contains n.

Original entry on oeis.org

1, 1, 2, 1, 2, 1, 3, 2, 1, 3, 2, 4, 1, 3, 2, 4, 1, 3, 5, 2, 4, 1, 3, 5, 2, 4, 6, 1, 3, 5, 2, 4, 6, 1, 3, 5, 7, 2, 4, 6, 1, 3, 5, 7, 2, 4, 6, 8, 1, 3, 5, 7, 2, 4, 6, 8, 1, 3, 5, 7, 9, 2, 4, 6, 8, 1, 3, 5, 7, 9, 2, 4, 6, 8, 10, 1, 3, 5, 7, 9, 2, 4, 6, 8, 10, 1, 3, 5, 7, 9, 11, 2, 4, 6, 8, 10, 1, 3, 5, 7, 9, 11, 2
Offset: 1

Views

Author

Clark Kimberling, Sep 09 2003

Keywords

Comments

A sequence that contains itself as a proper subsequence (infinitely many times); that is, a fractal sequence.

Examples

			Northwest corner of R:
1 2 4 6 9
3 5 8 11 15
7 10 14 18 23
12 16 21 26 32
19 24 30 36 43
a(10)=3 because 10 is in row 3.
		

Crossrefs

Formula

A087466(n)+1

A322026 Lexicographically earliest infinite sequence such that a(i) = a(j) => A007814(i) = A007814(j) and A007949(i) = A007949(j), for all i, j, where A007814 and A007949 give the 2- and 3-adic valuations of n.

Original entry on oeis.org

1, 2, 3, 4, 1, 5, 1, 6, 7, 2, 1, 8, 1, 2, 3, 9, 1, 10, 1, 4, 3, 2, 1, 11, 1, 2, 12, 4, 1, 5, 1, 13, 3, 2, 1, 14, 1, 2, 3, 6, 1, 5, 1, 4, 7, 2, 1, 15, 1, 2, 3, 4, 1, 16, 1, 6, 3, 2, 1, 8, 1, 2, 7, 17, 1, 5, 1, 4, 3, 2, 1, 18, 1, 2, 3, 4, 1, 5, 1, 9, 19, 2, 1, 8, 1, 2, 3, 6, 1, 10, 1, 4, 3, 2, 1, 20, 1, 2, 7, 4, 1, 5, 1, 6, 3
Offset: 1

Views

Author

Antti Karttunen, Dec 03 2018

Keywords

Comments

Restricted growth sequence transform of the ordered pair [A007814(n), A007949(n)].
For all i, j:
A305900(i) = A305900(j) => a(i) = a(j),
a(i) = a(j) => A122841(i) = A122841(j),
a(i) = a(j) => A244417(i) = A244417(j),
a(i) = a(j) => A322316(i) = A322316(j) => A072078(i) = A072078(j).
If and only if a(k) > a(i) for all k > i then k is in A003586, - David A. Corneth, Dec 03 2018
That is, A003586 gives the positions of records (1, 2, 3, 4, 5, ...) in this sequence.
Sequence A126760 (without its initial zero) and this sequence are ordinal transforms of each other.

Crossrefs

Cf. A003586 (positions of records, the first occurrence of n), A007814, A007949, A065331, A071521, A072078, A087465, A122841, A126760 (ordinal transform), A322316, A323883, A323884.
Cf. also A247714 and A255975.

Programs

  • PARI
    up_to = 65537;
    rgs_transform(invec) = { my(om = Map(), outvec = vector(length(invec)), u=1); for(i=1, length(invec), if(mapisdefined(om,invec[i]), my(pp = mapget(om, invec[i])); outvec[i] = outvec[pp] , mapput(om,invec[i],i); outvec[i] = u; u++ )); outvec; };
    A007814(n) = valuation(n,2);
    A007949(n) = valuation(n,3);
    v322026 = rgs_transform(vector(up_to, n, [A007814(n), A007949(n)]));
    A322026(n) = v322026[n];
    
  • PARI
    A065331(n) = (3^valuation(n, 3)<A065331
    A071521(n) = { my(t=1/3); sum(k=0, logint(n, 3), t*=3; logint(n\t, 2)+1); }; \\ From A071521.
    A322026(n) = A071521(A065331(n)); \\ Antti Karttunen, Sep 08 2024

Formula

For s = A003586(n), a(s) = n = a((6k+1)*s) = a((6k-1)*s), where s is the n-th 3-smooth number and k > 0. - David A. Corneth, Dec 03 2018
A065331(n) = A003586(a(n)). - David A. Corneth, Dec 04 2018
From Antti Karttunen, Sep 08 2024: (Start)
a(n) = Sum{k=1..n} [A126760(k)==A126760(n)], where [ ] is the Iverson bracket.
a(n) = A071521(A065331(n)). [Found by Sequence Machine and also by LODA miner]
a(n) = A323884(25*n). [Conjectured by Sequence Machine]
(End)

A283734 Rank array, R, of the golden ratio, read by antidiagonals downwards.

Original entry on oeis.org

1, 2, 3, 4, 5, 7, 6, 8, 10, 12, 9, 11, 14, 16, 19, 13, 15, 18, 21, 24, 28, 17, 20, 23, 26, 30, 34, 38, 22, 25, 29, 32, 36, 41, 45, 50, 27, 31, 35, 39, 43, 48, 53, 58, 63, 33, 37, 42, 46, 51, 56, 61, 67, 72, 78, 40, 44, 49, 54, 59, 65, 70, 76, 82, 88, 95, 47
Offset: 1

Views

Author

Clark Kimberling, Mar 16 2017

Keywords

Comments

Every row intersperses all other rows, and every column intersperses all other columns. The array is the dispersion of the complement of column 1; column 1 is given by r(n) = r(n-1) + 1 + L(n), where L = lower Wythoff sequence (A000201).

Examples

			The corner of R begins:
1    2    4    6    9    13    17    22
3    5    8    11   15   20    25    31
7    10   14   18   23   29    35    42
12   16   21   26   32   39    46    54
19   24   30   36   43   51    59    68
28   34   41   48   56   65    74    84
38   45   53   61   70   80    90    101
50   58   67   76   86   97    108   120
Let t = golden ratio = (1 + sqrt(5))/2; then R(i,j) = rank of (j,i) when all nonnegative integer pairs (a,b) are ranked by the relation << defined as follows: (a,b) << (c,d) if a + b*t < c + d*t, and also (a,b) << (c,d) if a + b*t = c + d*t and b < d.  Thus R(2,1) = 10 is the rank of (1,2) in the list (0,0) << (1,0) << (0,1) << (2,0) << (1,1) << (3,0) << (0,2) << (2,1) << (4,0) << (1,2).
		

Crossrefs

Cf. A001622, A255977 (row 1), A283733 (column 1), A000201, A087465.

Programs

  • Mathematica
    r = 40; r1 = 12;(*r=# rows of T,r1=# rows to show*);
    c = 40; c1 = 12;(*c=# cols of T,c1=# cols to show*);
    s[0] = 1; s[n_] := s[n] = s[n - 1] + 1 + Floor[n*GoldenRatio];
    u = Table[s[n], {n, 0, 400}] (* A283733 *)
    v = Complement[Range[Max[u]], u];
    f[n_] := v[[n]]; Table[f[n], {n, 1, 30}]
    mex[list_] := NestWhile[#1 + 1 &, 1, Union[list][[#1]] <= #1 &, 1,
    Length[Union[list]]]; rows = {NestList[f, 1, c]};
    Do[rows = Append[rows, NestList[f, mex[Flatten[rows]], r]], {r}];
    w[i_, j_] := rows[[i, j]];
    TableForm[Table[w[i, j], {i, 1, r1}, {j, 1, c1}]]   (* A283734, array *)
    Flatten[Table[w[k, n - k + 1], {n, 1, c1}, {k, 1, n}]] (* A283734, sequence *)
    TableForm[Table[w[i, 1] + w[1, j] + (i - 1)*(j - 1) - 1, {i, 1, r1}, {j, 1, c1}]] (* A283734, array, by formula *)

Formula

R(i,j) = R(i,0) + R(0,j) + i*j - 1, for i>=1, j>=1.
Showing 1-6 of 6 results.