A053156 -id:A053156 - cp's OEIS frontend

A083329 a(0) = 1; for n > 0, a(n) = 3*2^(n-1) - 1.

1, 2, 5, 11, 23, 47, 95, 191, 383, 767, 1535, 3071, 6143, 12287, 24575, 49151, 98303, 196607, 393215, 786431, 1572863, 3145727, 6291455, 12582911, 25165823, 50331647, 100663295, 201326591, 402653183, 805306367, 1610612735, 3221225471, 6442450943

Offset: 0

Paul Barry, Apr 27 2003

Apart from leading term (which should really be 3/2), same as A055010.
Binomial transform of A040001. Inverse binomial transform of A053156.
a(n) = A105728(n+1,2). - Reinhard Zumkeller, Apr 18 2005
Row sums of triangle A133567. - Gary W. Adamson, Sep 16 2007
Row sums of triangle A135226. - Gary W. Adamson, Nov 23 2007
a(n) = number of partitions Pi of [n+1] (in standard increasing form) such that the permutation Flatten[Pi] avoids the patterns 2-1-3 and 3-1-2. Example: a(3)=11 counts all 15 partitions of [4] except 13/24, 13/2/4 which contain a 2-1-3 and 14/23, 14/2/3 which contain a 3-1-2. Here "standard increasing form" means the entries are increasing in each block and the blocks are arranged in increasing order of their first entries. - David Callan, Jul 22 2008
An elephant sequence, see A175654. For the corner squares four A[5] vectors, with decimal values 42, 138, 162, 168, lead to this sequence. For the central square these vectors lead to the companion sequence A003945. - Johannes W. Meijer, Aug 15 2010
The binary representation of a(n) has n+1 digits, where all digits are 1's except digit n-1. For example: a(4) = 23 = 10111 (2). - Omar E. Pol, Dec 02 2012
Row sums of triangle A209561. - Reinhard Zumkeller, Dec 26 2012
If a Stern's sequence based enumeration system of positive irreducible fractions is considered (for example, A007305/A047679, A162909/A162910, A071766/A229742, A245325/A245326, ...), and if it is organized by blocks or levels (n) with 2^n terms (n >= 0), and the fractions, term by term, are summed at each level n, then the resulting sequence of integers is a(n) + 1/2, apart from leading term (which should be 1/2). - Yosu Yurramendi, May 23 2015
For n >= 2, A083329(n) in binary representation is a string [101..1], also 10 followed with (n-1) 1's. For n >= 3, A036563(n) in binary representation is a string [1..101], also (n-2) 1's followed with 01. Thus A083329(n) is a reflection of the binary representation of A036563(n+1). Example: A083329(5) = 101111 in binary, A036563(6) = 111101 in binary. - Ctibor O. Zizka, Nov 06 2018
For n > 0, a(n) is the minimum number of turns in (n+1)-dimensional Euclidean space needed to visit all 2^(n+1) vertices of the (n+1)-cube (e.g., {0,1}^(n+1)) and return to the starting point, moving along straight-line segments between turns (turns may occur elsewhere in R^(n+1)). - Marco Ripà, Aug 14 2025

			a(0) = (3*2^0 - 2 + 0^0)/2 = 2/2 = 1 (use 0^0=1).

Reinhard Zumkeller, Table of n, a(n) for n = 0..1000
M. Griffiths, I. Mezo, A generalization of Stirling Numbers of the Second Kind via a special multiset, JIS 13 (2010) #10.2.5.
Sergey Kitaev, Jeffrey Remmel, Mark Tiefenbruck, Quadrant Marked Mesh Patterns in 132-Avoiding Permutations II, Electronic Journal of Combinatorial Number Theory, Volume 15 #A16. (arXiv:1302.2274)
Agustín Moreno Cañadas, Hernán Giraldo, Gabriel Bravo Rios, On the Number of Sections in the Auslander-Reiten Quiver of Algebras of Dynkin Type, Far East Journal of Mathematical Sciences (FJMS), Vol. 101, No. 8 (2017), pp. 1631-1654.
Roberto Rinaldi and Marco Ripà, Optimal cycles enclosing all the nodes of a k-dimensional hypercube, arXiv:2212.11216 [math.CO], 2022.
Index entries for linear recurrences with constant coefficients, signature (3,-2).

Essentially the same as A055010 and A052940.
Cf. A000225, A052955, A133567, A135226.
Cf. A007505 (primes).
Cf. A266550 (independence number of the n-Mycielski graph).

a083329 n = a083329_list !! n
a083329_list = 1 : iterate ((+ 1) . (* 2)) 2
-- Reinhard Zumkeller, Dec 26 2012, Feb 22 2012

[1] cat [3*2^(n-1)-1: n in [1..40]]; // Vincenzo Librandi, Jan 01 2016

seq(ceil((2^i+2^(i+1)-2)/2), i=0..31); # Zerinvary Lajos, Oct 02 2007

a[1] = 2; a[n_] := 2a[n - 1] + 1; Table[ a[n], {n, 31}] (* Robert G. Wilson v, May 04 2004 *)
Join[{1}, LinearRecurrence[{3, -2}, {2, 5}, 40]] (* Vincenzo Librandi, Jan 01 2016 *)

a(n)=(3*2^n-2+0^n)/2 \\ Charles R Greathouse IV, Sep 24 2015

a(n) = (3*2^n - 2 + 0^n)/2.
G.f.: (1-x+x^2)/((1-x)*(1-2*x)). [corrected by Martin Griffiths, Dec 01 2009]
E.g.f.: (3*exp(2*x) - 2*exp(x) + exp(0))/2.
a(0) = 1, a(n) = sum of all previous terms + n. - Amarnath Murthy, Jun 20 2004
a(n) = 3*a(n-1) - 2*a(n-2) for n > 2, a(0)=1, a(1)=2, a(2)=5. - Philippe Deléham, Nov 29 2013
From Bob Selcoe, Apr 25 2014: (Start)
a(n) = (...((((((1)+1)*2+1)*2+1)*2+1)*2+1)...), with n+1 1's, n >= 0.
a(n) = 2*a(n-1) + 1, n >= 2.
a(n) = 2^n + 2^(n-1) - 1, n >= 2. (End)
a(n) = A086893(n) + A061547(n+1), n > 0. - Yosu Yurramendi, Jan 16 2017

A288638 Number A(n,k) of n-digit biquanimous strings using digits {0,1,...,k}; square array A(n,k), n>=0, k>=0, read by antidiagonals.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 3, 4, 1, 1, 1, 4, 10, 8, 1, 1, 1, 5, 19, 33, 16, 1, 1, 1, 6, 31, 92, 106, 32, 1, 1, 1, 7, 46, 201, 421, 333, 64, 1, 1, 1, 8, 64, 376, 1206, 1830, 1030, 128, 1, 1, 1, 9, 85, 633, 2841, 6751, 7687, 3153, 256, 1

Offset: 0

Alois P. Heinz, Jun 12 2017

A biquanimous string is a string whose digits can be split into two groups with equal sums.

			A(2,2) = 3: 00, 11, 22.
A(3,2) = 10: 000, 011, 022, 101, 110, 112, 121, 202, 211, 220.
A(3,3) = 19: 000, 011, 022, 033, 101, 110, 112, 121, 123, 132, 202, 211, 213, 220, 231, 303, 312, 321, 330.
A(4,1) = 8: 0000, 0011, 0101, 0110, 1001, 1010, 1100, 1111.
Square array A(n,k) begins:
  1,  1,    1,    1,     1,      1,      1,      1, ...
  1,  1,    1,    1,     1,      1,      1,      1, ...
  1,  2,    3,    4,     5,      6,      7,      8, ...
  1,  4,   10,   19,    31,     46,     64,     85, ...
  1,  8,   33,   92,   201,    376,    633,    988, ...
  1, 16,  106,  421,  1206,   2841,   5801,  10696, ...
  1, 32,  333, 1830,  6751,  19718,  48245, 104676, ...
  1, 64, 1030, 7687, 36051, 128535, 372345, 939863, ...

Alois P. Heinz, Antidiagonals n = 0..30, flattened

Columns k=0-9 give: A000012, A011782, A053156, A288687, A288688, A288689, A288690, A288691, A288692, A065024.
Rows n=0+1,2-3 give: A000012, A000027(k+1), A005448(k+1).
Main diagonal gives A288693.
Cf. A064544, A064914.

b:= proc(n, k, s) option remember;
      `if`(n=0, `if`(s={}, 0, 1), add(b(n-1, k, select(y->
       y<=(n-1)*k, map(x-> [abs(x-i), x+i][], s))), i=0..k))
    end:
A:= (n, k)-> b(n, k, {0}):
seq(seq(A(n, d-n), n=0..d), d=0..12);

b[n_, k_, s_] := b[n, k, s] = If[n == 0, If[s == {}, 0, 1], Sum[b[n-1, k, Select[Flatten[{Abs[#-i], #+i}& /@ s], # <= (n-1)*k&]], {i, 0, k}]];
A[n_, k_] := b[n, k, {0}];
Table[A[n, d-n], {d, 0, 10}, {n, 0, d}] // Flatten (* Jean-François Alcover, Jun 08 2018, from Maple *)

A294201 Irregular triangle read by rows: T(n,k) is the number of k-partitions of {1..3n} that are invariant under a permutation consisting of n 3-cycles (1 <= k <= 3n).

Original entry on oeis.org

1, 0, 1, 1, 1, 3, 2, 0, 1, 1, 3, 10, 12, 3, 9, 3, 0, 1, 1, 7, 33, 59, 30, 67, 42, 6, 18, 4, 0, 1, 1, 15, 106, 270, 216, 465, 420, 120, 235, 100, 10, 30, 5, 0, 1, 1, 31, 333, 1187, 1365, 3112, 3675, 1596, 2700, 1655, 330, 605, 195, 15, 45, 6, 0, 1

Offset: 1

Andrew Howroyd, Oct 24 2017

T(n,k) = coefficient of x^k for A(3,n)(x) in Gilbert and Riordan's article. - Robert A. Russell, Jun 13 2018

			Triangle begins:
  1,  0,   1;
  1,  1,   3,   2,   0,   1;
  1,  3,  10,  12,   3,   9,   3,   0,   1;
  1,  7,  33,  59,  30,  67,  42,   6,  18,   4,  0,  1;
  1, 15, 106, 270, 216, 465, 420, 120, 235, 100, 10, 30, 5, 0, 1;
  ...
Case n=2: Without loss of generality the permutation of two 3-cycles can be taken as (123)(456). The second row is [1, 1, 3, 2, 0, 1] because the set partitions that are invariant under this permutation in increasing order of number of parts are {{1, 2, 3, 4, 5, 6}}; {{1, 2, 3}, {4, 5, 6}}; {{1, 4}, {2, 5}, {3, 6}}, {{1, 5}, {2, 6}, {3, 4}}, {{1, 6}, {2, 4}, {3, 5}}; {{1, 2, 3}, {4}, {5}, {6}}, {{1}, {2}, {3}, {4, 5, 6}}, {{1}, {2}, {3}, {4}, {5}, {6}}.

Andrew Howroyd, Table of n, a(n) for n = 1..1395
E. N. Gilbert and J. Riordan, Symmetry types of periodic sequences, Illinois J. Math., 5 (1961), 657-665.

Row sums are A002874.
Column k=3 gives A053156.
Maximum row values are A294202.
Unrelated to A002875.
Cf. A002872, A002873, A293181.

T:= proc(n, k) option remember; `if`([n, k]=[0, 0], 1, 0)+
     `if`(n>0 and k>0, k*T(n-1, k)+T(n-1, k-1)+T(n-1, k-3), 0)
    end:
seq(seq(T(n, k), k=1..3*n), n=1..8);  # Alois P. Heinz, Sep 20 2019

T[n_, k_] := T[n,k] = If[n>0 && k>0, k T[n-1,k] + T[n-1,k-1] + T[n-1,k-3], Boole[n==0 && k==0]] (* modification of Gilbert & Riordan recursion *)
Table[T[n, k], {n,1,10}, {k,1,3n}] // Flatten (* Robert A. Russell, Jun 13 2018 *)

\\ see A056391 for Polya enumeration functions
T(n,k)={my(ci=PermCycleIndex(CylinderPerms(3,n)[2])); StructsByCycleIndex(ci,k) - if(k>1,StructsByCycleIndex(ci,k-1))}
for (n=1, 6, for(k=1, 3*n, print1(T(n,k), ", ")); print);

G(n)={Vec(-1+serlaplace(exp(sumdiv(3, d, y^d*(exp(d*x + O(x*x^n))-1)/d))))}
{ my(A=G(6)); for(n=1, #A, print(Vecrev(A[n]/y))) } \\ Andrew Howroyd, Sep 20 2019

T(n,k) = [n==0 & k==0] + [n>0 & k>0] * (k*T(n-1,k) + T(n-1,k-1) + T(n-1,k-3)). - Robert A. Russell, Jun 13 2018

T(n,k) = n!*[x^n*y^k] exp(Sum_{d|3} y^d*(exp(d*x) - 1)/d). - Andrew Howroyd, Sep 20 2019

A052390 Number of 4-element intersecting families (with not necessarily distinct sets) whose union is an n-element set.

Original entry on oeis.org

1, 7, 71, 956, 15116, 254397, 4318511, 72331966, 1188180386, 19152566087, 303768582701, 4755204310776, 73675434833456, 1132450098258577, 17301032324486891, 263098797953058386, 3987051131522775326

Offset: 1

Vladeta Jovovic, Goran Kilibarda, Mar 11 2000

G. C. Greubel, Table of n, a(n) for n = 1..845
V. Jovovic, G. Kilibarda, On the number of Boolean functions in the Post classes F^{mu}_8, Diskretnaya Matematika, 11 (1999), no. 4, 127-138.
V. Jovovic, G. Kilibarda, On the number of Boolean functions in the Post classes F^{mu}_8, (English translation), Discrete Mathematics and Applications, 9, (1999), no. 6.
Index entries for linear recurrences with constant coefficients, signature (71, -2205, 39495, -452523, 3473673, -18166175, 64427005, -150923976, 220549356, -178819920, 59875200).

Cf. A051181, A053156, A053157.

[(15^n - 6*11^n + 12*9^n - 8^n - 10*7^n + 15*6^n - 24*5^n + 19*4^n + 5*3^n - 11*2^n + 6)/24: n in [1..50]]; // G. C. Greubel, Oct 08 2017

Table[(15^n - 6*11^n + 12*9^n - 8^n - 10*7^n + 15*6^n - 24*5^n + 19*4^n + 5*3^n - 11*2^n + 6)/4!, {n, 1, 50}] (* G. C. Greubel, Oct 08 2017 *)

for(n=1,50, print1((15^n - 6*11^n + 12*9^n - 8^n - 10*7^n + 15*6^n - 24*5^n + 19*4^n + 5*3^n - 11*2^n + 6)/4!, ", ")) \\ G. C. Greubel, Oct 08 2017

a(n) = (15^n - 6*11^n + 12*9^n - 8^n - 10*7^n + 15*6^n - 24*5^n + 19*4^n + 5*3^n - 11*2^n + 6)/4!.

G.f.: -x * (14968800*x^10 - 34931250*x^9 + 36757686*x^8 - 21625925*x^7 + 7809481*x^6 - 1821016*x^5 + 279853*x^4 - 28145*x^3 + 1779*x^2 - 64*x + 1) / ((x-1)*(2*x-1)*(3*x-1)*(4*x-1)*(5*x-1)*(6*x-1)*(7*x-1)*(8*x-1)*(9*x-1)*(11*x-1)*(15*x-1)). - Colin Barker, Jul 30 2012

cp's OEIS Frontend

A083329 a(0) = 1; for n > 0, a(n) = 3*2^(n-1) - 1.

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A288638 Number A(n,k) of n-digit biquanimous strings using digits {0,1,...,k}; square array A(n,k), n>=0, k>=0, read by antidiagonals.

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A294201 Irregular triangle read by rows: T(n,k) is the number of k-partitions of {1..3n} that are invariant under a permutation consisting of n 3-cycles (1 <= k <= 3n).

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A052390 Number of 4-element intersecting families (with not necessarily distinct sets) whose union is an n-element set.

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A083330 a(n) = (3*4^n - 2*3^n + 2^n)/2.

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A083330 a(n) = (34^n - 23^n + 2^n)/2.