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.

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A099263 a(n) = (1/40320)*8^n + (1/1440)*6^n + (1/360)*5^n + (1/64)*4^n + (11/180)*3^n + (53/288)*2^n + 103/280. Partial sum of Stirling numbers of second kind S(n,i), i=1..8 (i.e., a(n) = Sum_{i=1..8} S(n,i)).

Original entry on oeis.org

1, 2, 5, 15, 52, 203, 877, 4140, 21146, 115929, 677359, 4189550, 27243100, 184941915, 1301576801, 9433737120, 69998462014, 529007272061, 4054799902003, 31415584940850, 245382167055488, 1928337630016767, 15222915798289765, 120582710957928740, 957566218595705122, 7618489083072350433
Offset: 1

Views

Author

Nelma Moreira, Oct 10 2004

Keywords

Comments

Density of regular language L over {1,2,3,4,5,6,7,8} (i.e., number of strings of length n in L) described by a regular expression with c = 8: Sum_{i=1..c} Product_{j=1..i} (j(1+...+j)*), where "Sum" stands for union and "Product" for concatenation.

Crossrefs

A row of the array in A278984.
Cf. A008277 (Stirling2), A248925.

Programs

  • Magma
    [(1/40320)*8^n+(1/1440)*6^n+(1/360)*5^n+(1/64)*4^n +(11/180)*3^n+(53/288)*2^n+103/280: n in [1..30]]; // Vincenzo Librandi, Jul 27 2017
    
  • Mathematica
    CoefficientList[Series[-(3641 x^6 - 6583 x^5 + 4566 x^4 - 1579 x^3 + 290 x^2 - 27 x + 1) / ((x - 1) (2 x - 1) (3 x - 1) (4 x - 1) (5 x - 1) (6 x - 1) (8 x - 1)), {x, 0, 30}], x] (* Vincenzo Librandi, Jul 27 2017 *)
    Table[Sum[StirlingS2[n, k], {k, 0, 8}], {n, 1, 30}] (* Robert A. Russell, Apr 25 2018 *)
    LinearRecurrence[{29,-343,2135,-7504,14756,-14832,5760},{1,2,5,15,52,203,877},30] (* Harvey P. Dale, Aug 27 2019 *)
  • PARI
    a(n) = (1/40320)*8^n + (1/1440)*6^n + (1/360)*5^n + (1/64)*4^n + (11/180)*3^n + (53/288)*2^n + 103/280; \\ Altug Alkan, Apr 25 2018

Formula

For c = 8, a(n) = c^n/c! + Sum_{k=1..c-2} k^n/k! * Sum_{j=2..c-k} (-1)^j/j!, or = Sum_{k=1..c} g(k, c)*k^n, where g(1, 1) = 1, g(1, c) = g(1, c-1) + (-1)^(c-1)/(c-1)! for c > 1, and g(k, c) = g(k-1, c-1)/k for c > 1 and 2 <= k <= c.
G.f.: -x*(3641*x^6 - 6583*x^5 + 4566*x^4 - 1579*x^3 + 290*x^2 - 27*x + 1) / ((x-1)*(2*x-1)*(3*x-1)*(4*x-1)*(5*x-1)*(6*x-1)*(8*x-1)). [Colin Barker, Dec 05 2012]
a(n) = Sum_{k=0..8} Stirling2(n,k).
G.f.: Sum_{j=0..k} A248925(k,j)*x^j / Product_{j=1..k} (1 - j*x) with k = 8. - Robert A. Russell, Apr 25 2018

Extensions

More terms from Michel Marcus, Jan 05 2025

A203641 Number of arrays of n 0..10 integers with new values introduced in order 0..10 but otherwise unconstrained.

Original entry on oeis.org

1, 2, 5, 15, 52, 203, 877, 4140, 21147, 115975, 678570, 4213596, 27644358, 190895863, 1382847419, 10477213268, 82797679445, 680685836527, 5806124780384, 51245294979716, 466668627500968, 4371727233798927, 42000637216351225
Offset: 1

Views

Author

R. H. Hardin, Jan 04 2012

Keywords

Comments

From Danny Rorabaugh, Mar 03 2015: (Start)
a(n) is also the number of ways of placing n labeled balls into 11 indistinguishable boxes.
a(n) is also the number of word structures of length n using an 11-ary alphabet.
(End)

Crossrefs

Column k=10 of A203647.

Programs

  • Maple
    f:= n -> add(Stirling2(n,k),k=1..11):
    map(f, [$1..100]); # Robert Israel, Aug 08 2016
  • PARI
    a(n) = sum(k=1,11,stirling(n,k, 2)); \\ Michel Marcus, Mar 03 2015

Formula

Empirical: a(n) = 56*a(n-1) -1365*a(n-2) +19020*a(n-3) -167223*a(n-4) +965328*a(n-5) -3686255*a(n-6) +9133180*a(n-7) -13926276*a(n-8) +11655216*a(n-9) -3991680*a(n-10).
a(n) = Sum_{k=1..11} stirling2(n,k). - Danny Rorabaugh, Mar 03 2015
G.f.: Sum_{k=1..11} Product_{j=1..k} x/(1-j*x). This confirms the empirical recurrence. - Robert Israel, Aug 08 2016

A209744 T(n,k)=Number of nXk 0..5 arrays with every 2X2 subblock containing exactly one value repeat, and new values 0..5 introduced in row major order.

Original entry on oeis.org

1, 2, 2, 5, 6, 5, 15, 57, 57, 15, 52, 700, 2025, 700, 52, 203, 10594, 103373, 103373, 10594, 203, 876, 183240, 6262064, 20611956, 6262064, 183240, 876, 4111, 3412100, 404495219, 4474325828, 4474325828, 404495219, 3412100, 4111, 20648, 65953664
Offset: 1

Views

Author

R. H. Hardin Mar 12 2012

Keywords

Comments

Table starts
....1........2.............5................15.....................52
....2........6............57...............700..................10594
....5.......57..........2025............103373................6262064
...15......700........103373..........20611956.............4474325828
...52....10594.......6262064........4474325828..........3309942226828
..203...183240.....404495219......991613495404.......2462887498725440
..876..3412100...26715084257...220845828478730....1834383283218723590
.4111.65953664.1777603386801.49242046909442868.1366486932112899379170

Examples

			Some solutions for n=5 k=3
..0..0..0....0..0..0....0..0..0....0..0..0....0..0..0....0..0..0....0..0..1
..1..2..1....1..2..1....1..2..1....1..2..1....1..2..1....1..2..1....1..2..0
..0..1..0....3..3..1....2..3..1....0..0..1....0..0..0....2..0..0....0..0..1
..1..2..0....0..1..2....1..2..3....2..1..2....1..3..4....0..3..4....1..2..0
..3..1..0....0..3..1....0..0..0....1..0..0....1..5..3....0..5..4....1..0..3
		

Crossrefs

Column 1 is A056273

A320955 Square array read by ascending antidiagonals: A(n, k) (n >= 0, k >= 0) = Sum_{j=0..n-1} (!j/j!)*((n - j)^k/(n - j)!) if k > 0 and 1 if k = 0. Here !n denotes the subfactorial of n.

Original entry on oeis.org

1, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 1, 2, 1, 0, 1, 1, 2, 4, 1, 0, 1, 1, 2, 5, 8, 1, 0, 1, 1, 2, 5, 14, 16, 1, 0, 1, 1, 2, 5, 15, 41, 32, 1, 0, 1, 1, 2, 5, 15, 51, 122, 64, 1, 0, 1, 1, 2, 5, 15, 52, 187, 365, 128, 1, 0, 1, 1, 2, 5, 15, 52, 202, 715, 1094, 256, 1, 0
Offset: 0

Views

Author

Peter Luschny, Nov 05 2018

Keywords

Comments

Arndt and Sloane (see the link and A278984) identify the sequence to give "the number of words of length n over an alphabet of size b that are in standard order" and provide the formula Sum_{j = 1..b} Stirling_2(n, j) assuming b >= 1 and j >= 1. Compared to the array as defined here this misses the first row and the first column of our array.
The method used here is the special case of a general method described in A320956 applied to the function exp. For applications to other functions see the cross references.
A(k,n) is the number of color patterns (set partitions) for an oriented row of length n using up to k colors (subsets). Two color patterns are equivalent if the colors are permuted. For A(3,4) = 14, the six achiral patterns are AAAA, AABB, ABAB, ABBA, ABBC, and ABCA; the eight chiral patterns are the four chiral pairs AAAB-ABBB, AABA-ABAA, AABC-ABCC, and ABAC-ABCB. - Robert A. Russell, Nov 10 2018

Examples

			Array starts:
n\k   0  1  2  3   4   5    6    7     8      9  ...
----------------------------------------------------
[0]   1, 0, 0, 0,  0,  0,   0,   0,    0,     0, ...  A000007
[1]   1, 1, 1, 1,  1,  1,   1,   1,    1,     1, ...  A000012
[2]   1, 1, 2, 4,  8, 16,  32,  64,  128,   256, ...  A011782
[3]   1, 1, 2, 5, 14, 41, 122, 365, 1094,  3281, ...  A124302
[4]   1, 1, 2, 5, 15, 51, 187, 715, 2795, 11051, ...  A124303
[5]   1, 1, 2, 5, 15, 52, 202, 855, 3845, 18002, ...  A056272
[6]   1, 1, 2, 5, 15, 52, 203, 876, 4111, 20648, ...  A056273, ?A284727
[7]   1, 1, 2, 5, 15, 52, 203, 877, 4139, 21110, ...
[8]   1, 1, 2, 5, 15, 52, 203, 877, 4140, 21146, ...
[9]   1, 1, 2, 5, 15, 52, 203, 877, 4140, 21147, ...
----------------------------------------------------
Seen as a triangle given by the descending antidiagonals:
[0]             1
[1]            0, 1
[2]          0, 1, 1
[3]        0, 1, 1, 1
[4]       0, 1, 2, 1, 1
[5]     0, 1, 4, 2, 1, 1
[6]    0, 1, 8, 5, 2, 1, 1
[7]  0, 1, 16, 14, 5, 2, 1, 1
		

Crossrefs

Antidiagonal sums (and row sums of the triangle): A320964.
Cf. this sequence (exp), A320962 (log(x+1)), A320956 (sec+tan), A320958 (arcsin), A320959 (arctanh).
Cf. A320750 (unoriented), A320751 (chiral), A305749 (achiral).

Programs

  • Maple
    A := (n, k) -> if k = 0 then 1 else add(A008290(n, n-j)*(n-j)^k, j=0..n-1)/n! fi:
    seq(lprint(seq(A(n, k), k=0..9)), n=0..9); # Prints the array row-wise.
    seq(seq(A(n-k, k), k=0..n), n=0..11); # Gives the array as listed.
  • Mathematica
    T[n_, 0] := 1; T[n_, k_] := Sum[(Subfactorial[j]/Factorial[j])((n - j)^k/(n - j)!), {j, 0, n - 1}]; Table[T[n - k, k], {n, 0, 11}, {k, 0, n}] // Flatten
    Table[Sum[StirlingS2[k, j], {j, 0, n-k}], {n, 0, 11}, {k, 0, n}] // Flatten (* Robert A. Russell, Nov 10 2018 *)

Formula

A(n, k) = (1/n!)*Sum_{j=0..n-1} A008290(n, n-j)*(n-j)^k if k > 0.
If one drops the special case A(n, 0) = 1 from the definition then column 0 becomes Sum_{k=0..n} (-1)^k/k! = A103816(n)/A053556(n).
Row n is given for k >= 1 by a_n(k), where
a_0(k) = 0^k/0!.
a_1(k) = 1^k/1!.
a_2(k) = (2^k)/2!.
a_3(k) = (3^k + 3)/3!.
a_4(k) = (6*2^k + 4^k + 8)/4!.
a_5(k) = (20*2^k + 10*3^k + 5^k + 45)/5!.
a_6(k) = (135*2^k + 40*3^k + 15*4^k + 6^k + 264)/6!.
a_7(k) = (924*2^k + 315*3^k + 70*4^k + 21*5^k + 7^k + 1855)/7!.
a_8(k) = (7420*2^k + 2464*3^k + 630*4^k + 112*5^k + 28*6^k + 8^k + 14832)/8!.
Note that the coefficients of the generating functions a_n are the recontres numbers A000240, A000387, A000449, ...
Rewriting the formulas with exponential generating functions for the rows we have egf(n) = Sum_{k=0..n} !k*binomial(n,k)*exp(x*(n-k)) and A(n, k) = (k!/n!)*[x^k] egf(n). In this formulation no special rule for the case k = 0 is needed.
The rows converge to the Bell numbers. Convergence here means that for every fixed k the terms in column k differ from A000110(k) only for finitely many indices.
A(n, n) are the Bell numbers A000110(n) for n >= 0.
Let S(n, k) = Bell(n+k+1) - A(n, k+n+1) for n >= 0 and k >= 0, then the square array S(n, k) read by descending antidiagonals equals provable the triangle A137650 and equals empirical the transpose of the array A211561.

A164863 Number of ways of placing n labeled balls into 9 indistinguishable boxes; word structures of length n using a 9-ary alphabet.

Original entry on oeis.org

1, 1, 2, 5, 15, 52, 203, 877, 4140, 21147, 115974, 678514, 4211825, 27602602, 190077045, 1368705291, 10254521370, 79527284317, 635182667816, 5199414528808, 43426867585575, 368654643520692, 3170300933550687, 27542984610086665, 241205285284001240
Offset: 0

Views

Author

Alois P. Heinz, Aug 28 2009

Keywords

Crossrefs

Programs

  • Maple
    # first program:
    a:= n-> ceil(103/560*2^n +53/864*3^n +11/720*4^n +5^n/320 +6^n/2160 +7^n/10080 +9^n/362880): seq(a(n), n=0..25);
    # second program:
    a:= n-> add(Stirling2(n, k), k=0..9): seq(a(n), n=0..25);
  • Mathematica
    Table[Sum[StirlingS2[n, k], {k, 0, 9}], {n, 0, 30}] (* Robert A. Russell, Apr 25 2018 *)

Formula

a(n) = Sum_{k=0..9} stirling2 (n,k).
a(n) = ceiling (103/560*2^n +53/864*3^n +11/720*4^n +5^n/320 +6^n/2160 +7^n/10080 +9^n/362880).
G.f.: (16687*x^8 -67113*x^7 +88620*x^6 -56993*x^5 +20529*x^4 -4353*x^3 +539*x^2 -36*x+1) / ((9*x-1) *(7*x-1) *(6*x-1) *(5*x-1) *(4*x-1) *(3*x-1) *(2*x-1) *(x-1)).
G.f.: Sum_{j=0..k} A248925(k,j)*x^j / Product_{j=1..k} 1-j*x with k=9. - Robert A. Russell, Apr 25 2018

A305752 Number of achiral color patterns (set partitions) in a row or cycle of length n with 6 or fewer colors (subsets).

Original entry on oeis.org

1, 1, 2, 3, 7, 12, 31, 58, 159, 312, 883, 1774, 5103, 10368, 30067, 61414, 178815, 366168, 1068259, 2190190, 6395919, 13120944, 38335123, 78665590, 229890591, 471814344, 1378985155, 2830350526, 8272839855, 16980500640, 49633834099, 101878204486
Offset: 0

Views

Author

Robert A. Russell, Jun 09 2018

Keywords

Comments

An equivalent color pattern is obtained when we permute the colors. Thus all permutations of ABCDE are equivalent, as are AABCDEF and BBCDEFA. A color pattern is achiral if it is equivalent to its reversal. Rotations of the colors of a cycle are equivalent, so for cycles AABCCDEF = BCCDEFAA = CCDEFAAB.

Examples

			For a(5) = 12, the achiral patterns for both rows and cycles are AAAAA, AABAA, ABABA, ABBBA, AABCC, ABACA, ABBBC, ABCAB, ABCBA, ABCBD, ABCDA, and ABCDE.
		

Crossrefs

Sixth column of A305749.
Cf. A056273 (oriented), A056325 (unoriented), A320936 (chiral), for rows.
Cf. A056294 (oriented), A056356 (unoriented), A320746 (chiral), for cycles.

Programs

  • Maple
    seq(coeff(series((1-10*x^2+x^3+29*x^4-6*x^5-25*x^6+8*x^7)/((1-x)*(1-2*x^2)*(1-3*x^2)*(1-6*x^2)),x,n+1), x, n), n = 0 .. 35); # Muniru A Asiru, Oct 30 2018
  • Mathematica
    Table[If[EvenQ[n], StirlingS2[(n+12)/2, 6] - 19 StirlingS2[(n+10)/2, 6] + 140 StirlingS2[(n+8)/2, 6] - 501 StirlingS2[(n+6)/2, 6] + 887 StirlingS2[(n+4)/2, 6] - 692 StirlingS2[(n+2)/2, 6] + 160 StirlingS2[n/2, 6], StirlingS2[(n+11)/2, 6] - 18 StirlingS2[(n+9)/2, 6] + 124 StirlingS2[(n+7)/2, 6] - 404 StirlingS2[(n+5)/2, 6] + 613 StirlingS2[(n+3)/2, 6] - 340 StirlingS2[(n+1)/2, 6]], {n, 0, 40}]
    Ach[n_, k_] := Ach[n,k] = If[n<2, Boole[n==k && n>=0], k Ach[n-2,k] + Ach[n-2,k-1] + Ach[n-2,k-2]]; (* A304972 *)
    k=6; Table[Sum[Ach[n, j], {j, 0, k}], {n, 0, 40}]
    CoefficientList[Series[(1-10x^2+x^3+29x^4-6x^5-25x^6+8x^7) / ((1-x)(1-2x^2)(1-3x^2)(1-6 x^2)), {x, 0, 40}], x]
    LinearRecurrence[{1,11,-11,-36,36,36,-36},{1,1,2,3,7,12,31,58},40]
    Join[{1}, Table[If[EvenQ[n], (36 + 45 2^(n/2) + 40 3^(n/2) + 19 6^(n/2)) / 180, (72 + 45 2^((n+1)/2) + 40 3^((n+1)/2) + 13 6^((n+1)/2)) / 360], {n,40}]]

Formula

a(n) = Sum_{j=0..6} Ach(n,j), where Ach(n,k) = [n>1] * (k*T(n-2,k) + T(n-2,k-1) + T(n-2,k-2)) + [0<=n<2 & n==k].
G.f.: (1-10x^2+x^3+29x^4-6x^5-25x^6+8x^7) / ((1-x)*(1-2x^2)*(1-3x^2)*(1-6x^2)).
a(2m) = S2(m+6,6) - 19*S2(m+5,6) + 140*S2(m+4,6) - 501*S2(m+3,6) + 887*S2(m+2,6) - 692*S2(m+1,6) + 160*S2(m,6);
a(2m-1) = S2(m+5,6) - 18*S2(m+4,6) + 124*S2(m+3,6) - 404*S2(m+2,6) + 613*S2(m+1,6) - 340*S2(m,6), where S2(n,k) is the Stirling subset number A008277.
For n>0, a(2m) = (36 + 45*2^m + 40*3^m + 19*6^m) / 180.
a(2m-1) = (72 + 45*2^m + 40*3^m + 13*6^m) / 360.
a(n) = 2*A056325(n) - A056273(n) = A056273(n) - 2*A320936(n) = A056325(n) - A320936(n).
a(n) = 2*A056356(n) - A056294(n) = A056294(n) - 2*A320746(n) = A056356(n) - A320936(n).
a(n) = A057427(n) + A052551(n-2) + A304973(n) + A304974(n) + A304975(n) + A304976(n).
a(n) = a(n-1) + 11*a(n-2) - 11*a(n-3) - 36*a(n-4) + 36*a(n-5) + 36*a(n-6) - 36*a(n-7). - Muniru A Asiru, Oct 30 2018

A320936 Number of chiral pairs of color patterns (set partitions) for a row of length n using 6 or fewer colors (subsets).

Original entry on oeis.org

0, 0, 1, 4, 20, 86, 409, 1976, 10168, 54208, 299859, 1699012, 9808848, 57335124, 338073107, 2004955824, 11936998016, 71253827696, 426061036747, 2550545918300, 15280090686256, 91588065861292, 549159350303235, 3293482358956552, 19755007003402944
Offset: 1

Views

Author

Robert A. Russell, Oct 27 2018

Keywords

Comments

Two color patterns are equivalent if the colors are permuted.
A chiral row is not equivalent to its reverse.
There are nonrecursive formulas, generating functions, and computer programs for A056273 and A305752, which can be used in conjunction with the first formula.

Examples

			For a(4)=4, the chiral pairs are AAAB-ABBB, AABA-ABAA, AABC-ABCC, and ABAC-ABCB.
		

Crossrefs

Column 6 of A320751.
Cf. A056273 (oriented), A056325 (unoriented), A305752 (achiral).

Programs

  • Mathematica
    Ach[n_, k_] := Ach[n, k] = If[n<2, Boole[n==k && n>=0], k Ach[n-2,k] + Ach[n-2,k-1] + Ach[n-2,k-2]] (* A304972 *)
    k=6; Table[Sum[StirlingS2[n,j]-Ach[n,j],{j,k}]/2,{n,40}]
    LinearRecurrence[{16, -84, 84, 685, -2140, 180, 7200, -8244, -4176, 11664, -5184}, {0, 0, 1, 4, 20, 86, 409, 1976, 10168, 54208, 299859}, 40]
  • PARI
    concat([0,0], Vec(x^3*(1 - 12*x + 40*x^2 + 18*x^3 - 308*x^4 + 376*x^5 + 364*x^6 - 882*x^7 + 378*x^8) / ((1 - x)*(1 - 2*x)*(1 - 3*x)*(1 - 4*x)*(1 - 6*x)*(1 - 2*x^2)*(1 - 3*x^2)*(1 - 6*x^2)) + O(x^40))) \\ Colin Barker, Nov 22 2018

Formula

a(n) = (A056273(n) - A305752(n))/2.
a(n) = A056273(n) - A056325(n).
a(n) = A056325(n) - A305752(n).
a(n) = A122746(n-2) + A320526(n) + A320527(n) + A320528(n) + A320529(n).
a(n) = Sum_{j=1..k} (S2(n,j) - Ach(n,j)) / 2, where k=6 is the maximum number of colors, S2 is the Stirling subset number A008277, and Ach(n,k) = [n>=0 & n<2 & n==k] + [n>1]*(k*Ach(n-2,k) + Ach(n-2,k-1) + Ach(n-2,k-2)).
From Colin Barker, Nov 22 2018: (Start)
G.f.: x^3*(1 - 12*x + 40*x^2 + 18*x^3 - 308*x^4 + 376*x^5 + 364*x^6 - 882*x^7 + 378*x^8) / ((1 - x)*(1 - 2*x)*(1 - 3*x)*(1 - 4*x)*(1 - 6*x)*(1 - 2*x^2)*(1 - 3*x^2)*(1 - 6*x^2)).
a(n) = 16*a(n-1) - 84*a(n-2) + 84*a(n-3) + 685*a(n-4) - 2140*a(n-5) + 180*a(n-6) + 7200*a(n-7) - 8244*a(n-8) - 4176*a(n-9) + 11664*a(n-10) - 5184*a(n-11) for n>11.
(End)

A206503 T(n,k)=Number of nXk 0..7 arrays with no element equal to another within a city block distance of two, and new values 0..7 introduced in row major order.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 2, 4, 4, 2, 5, 34, 65, 34, 5, 15, 481, 3130, 3130, 481, 15, 52, 8731, 178998, 502599, 178998, 8731, 52, 203, 174454, 10502458, 83045488, 83045488, 10502458, 174454, 203, 876, 3603244, 618242826, 13752277898, 38638317841, 13752277898
Offset: 1

Views

Author

R. H. Hardin Feb 08 2012

Keywords

Comments

Table starts
...1.......1.........1...........2...........5..........15............52
...1.......1.........4..........34.........481........8731........174454
...1.......4........65........3130......178998....10502458.....618242826
...2......34......3130......502599....83045488.13752277898.2277207309720
...5.....481....178998....83045488.38638317841
..15....8731..10502458.13752277898
..52..174454.618242826
.203.3603244

Examples

			Some solutions for n=4 k=3
..0..1..2....0..1..2....0..1..2....0..1..2....0..1..2....0..1..2....0..1..2
..2..3..0....3..4..5....2..3..0....2..3..4....2..3..0....2..3..0....3..4..0
..1..4..5....5..2..1....1..4..5....4..5..6....4..5..6....4..5..1....2..5..1
..5..0..1....6..7..3....5..2..1....6..1..7....6..7..1....3..0..6....0..3..6
		

Crossrefs

Column 1 is A056273(n-2)
Column 2 is A198976(n-1)

A056277 Number of primitive (aperiodic) word structures of length n using a 6-ary alphabet.

Original entry on oeis.org

1, 1, 4, 13, 51, 197, 875, 4096, 20643, 109246, 601491, 3402911, 19628063, 114699438, 676207572, 4010086352, 23874362199, 142508702805, 852124263683, 5101098123207, 30560194492576, 183176169456214
Offset: 1

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Author

Keywords

Comments

Permuting the alphabet will not change a word structure. Thus aabc and bbca have the same structure.

References

  • M. R. Nester (1999). Mathematical investigations of some plant interaction designs. PhD Thesis. University of Queensland, Brisbane, Australia. [See A056391 for pdf file of Chap. 2]

Crossrefs

Cf. A054721.

Formula

sum mu(d)*A056273(n/d) where d|n and n>0.

A284727 Dimensions of certain centralizer algebras associated with Bratelli diagram B(S_6, S_5).

Original entry on oeis.org

1, 1, 2, 5, 15, 52, 203, 876, 4111
Offset: 0

Views

Author

N. J. A. Sloane, Apr 07 2017

Keywords

Comments

Is this the same as A056273? - R. J. Mathar, Oct 22 2021
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