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.

Previous Showing 31-40 of 40 results.

A177607 Number of permutations of 3 copies of 1..n avoiding adjacent step pattern up, down, down, down, up.

Original entry on oeis.org

1, 1, 20, 1680, 359582, 156245130, 120386806922, 150097348110878, 283411248751268531
Offset: 0

Views

Author

R. H. Hardin, May 10 2010

Keywords

Crossrefs

Cf. A014606.

A177612 Number of permutations of 3 copies of 1..n avoiding adjacent step pattern up, down, up, up, up.

Original entry on oeis.org

1, 1, 20, 1680, 362082, 159459279, 124951069219, 158754672447498, 305860462403616044
Offset: 0

Views

Author

R. H. Hardin, May 10 2010

Keywords

Crossrefs

Cf. A014606.

A177616 Number of permutations of 3 copies of 1..n avoiding adjacent step pattern up, down, down, down, down, down.

Original entry on oeis.org

1, 1, 20, 1680, 369600, 168168000, 137150254800, 182209829636934, 368221858096998960
Offset: 0

Views

Author

R. H. Hardin, May 10 2010

Keywords

Crossrefs

Cf. A014606.

A177617 Number of permutations of 3 copies of 1..n avoiding adjacent step pattern up, down, down, down, down, up.

Original entry on oeis.org

1, 1, 20, 1680, 369600, 167510862, 135702841152, 178756061502340, 357729925926146006
Offset: 0

Views

Author

R. H. Hardin, May 10 2010

Keywords

Crossrefs

Cf. A014606.

A177629 Number of permutations of 3 copies of 1..n avoiding adjacent step pattern up, down, up, up, up, up.

Original entry on oeis.org

1, 1, 20, 1680, 369600, 167714730, 136194434423, 179979692293317, 361532596882040400
Offset: 0

Views

Author

R. H. Hardin, May 10 2010

Keywords

Crossrefs

Cf. A014606.

A177630 Number of permutations of 3 copies of 1..n avoiding adjacent step pattern up, up, down, down, down, down.

Original entry on oeis.org

1, 1, 20, 1680, 369600, 167895912, 136567215720, 180834782762247, 364064983677371040
Offset: 0

Views

Author

R. H. Hardin, May 10 2010

Keywords

Crossrefs

Cf. A014606.

A177635 Number of permutations of 3 copies of 1..n avoiding adjacent step pattern up, up, up, up, up, up.

Original entry on oeis.org

1, 1, 20, 1680, 369600, 168168000, 137225088000, 182499151015439, 369333660414653745, 1080107104118231632500, 4384231121059173932562000, 23913914175434871142808715000, 170693577054027116430454774306800, 1559452501977701854639515593122328400
Offset: 0

Views

Author

R. H. Hardin, May 10 2010

Keywords

Crossrefs

Cf. A014606.

Extensions

a(10)-a(13) from Alois P. Heinz, Aug 08 2018

A211310 a(n) = number |fdw(P,(n))| of entangled P-words with s=3.

Original entry on oeis.org

1, 18, 1566, 354456, 163932120, 134973740880, 180430456454640, 366311352681348480
Offset: 1

Views

Author

N. J. A. Sloane, Apr 08 2012

Keywords

Comments

See Jenca and Sarkoci for the precise definition.

Crossrefs

Formula

From Peter Bala, Sep 05 2012: (Start)
Conjectural e.g.f.: 2 - 1/A(x), where A(x) = sum {n = 0..inf} (3*n)!/6^n*x^n/n! is the e.g.f. for A014606 (also the o.g.f. for A025035).
If true, this leads to the recurrence equation: a(n) = (3*n)!/6^n - sum {k = 1..n-1} (3*k)!/6^k*binomial(n,k)*a(n-k) with a(1) = 1.
(End)

A266738 Number of words on {1,1,1,2,2,2,3,3,3,4,4,4,...,n,n,n} avoiding the pattern 12345.

Original entry on oeis.org

1, 1, 20, 1680, 369600, 117392909, 46121962742, 21198300356500, 11003612776114008, 6290031043253973544, 3887357166155963541538, 2562077915376091538040250, 1782153151031487742187453640, 1297781266782084301101836538690, 983066960483171632842827775906144
Offset: 0

Views

Author

N. J. A. Sloane, Jan 06 2016

Keywords

Crossrefs

Extensions

More terms from Alois P. Heinz, Jan 14 2016

A327410 Numbers represented by the partition coefficients of prime partitions.

Original entry on oeis.org

1, 6, 10, 20, 21, 36, 56, 78, 90, 105, 120, 171, 210, 252, 300, 364, 465, 528, 560, 741, 756, 792, 903, 990, 1140, 1176, 1485, 1540, 1680, 1830, 1953, 1980, 2346, 2520, 2600, 2628, 2775, 3240, 3432, 3570, 4095, 4368, 4851, 4960, 5253, 5460, 5886, 5984, 6105
Offset: 1

Views

Author

Peter Luschny, Sep 07 2019

Keywords

Comments

Given a partition pi = (p1, p2, p3, ...) we call the associated multinomial coefficient (p1+p2+ ...)! / (p1!*p2!*p3! ...) the 'partition coefficient' of pi and denote it by . We say 'k is represented by pi' if k = .
A partition is a prime partition if all parts are prime.

Examples

			(2*n)!/2^n (for n >= 1) is a subsequence because [2,2,...,2] (n times '2') is a prime partition. Similarly A327411(n) is a subsequence because [3,2,2,...,2] (n times '2') is a prime partition. (3*n)!/(6^n) and A327412 are subsequences for the same reason.
The representations are not unique. 1 is the represented by all partitions of the form [p], p prime. For example 210 is represented by [3, 2, 2] and by [19, 2]. The list below shows the partitions with the smallest sum.
1   <- [2],
6   <- [2, 2],
10  <- [3, 2],
20  <- [3, 3],
21  <- [5, 2],
36  <- [7, 2],
56  <- [5, 3],
78  <- [11, 2],
90  <- [2, 2, 2],
105 <- [13, 2],
120 <- [7, 3],
171 <- [17, 2],
210 <- [3, 2, 2],
252 <- [5, 5],
300 <- [23, 2].
		

Crossrefs

Programs

  • SageMath
    def A327410_list(n):
        res = []
        for k in range(2*n):
            P = Partitions(k, parts_in = prime_range(k+1))
            res += [multinomial(p) for p in P]
        return sorted(Set(res))[:n]
    print(A327410_list(20))
Previous Showing 31-40 of 40 results.