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A200583 Table read by rows, n >= 1, 1 <= k <= card(divisors(n)), T(n,k) meanders of length n and central angle of 360/d degrees, d the k-th divisor of n. 1
1, 2, 1, 4, 1, 8, 3, 1, 16, 1, 32, 10, 4, 1, 64, 1, 128, 35, 5, 1, 256, 22, 1, 512, 126, 6, 1, 1024, 1, 2048, 462, 134, 46, 7, 1, 4096, 1, 8192, 1716, 8, 1, 16384, 866, 94, 1, 32768, 6435, 485, 9, 1, 65536, 1, 131072, 24310, 5812, 190, 10, 1, 262144, 1, 524288 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

A meander is a closed curve drawn by arcs of equal length and central angle of equal magnitude, starting with a positively oriented arc.

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..482

Peter Luschny, Meander.

FORMULA

T(n,k) = A198060(d-1,n/d-1) where d is the k-th divisor of n (the divisors in natural order).

EXAMPLE

[ 1]            1

[ 2]          2, 1

[ 3]          4, 1

[ 4]        8, 3, 1

[ 5]         16, 1

[ 6]      32, 10, 4, 1

[ 7]         64, 1

[ 8]     128, 35, 5, 1

[ 9]       256, 22, 1

[10]     512, 126, 6, 1

[11]        1024, 1

[12] 2048, 462, 134, 46, 7, 1

MAPLE

A200583_row := proc(n) local i;

seq(A198060(i-1, n/i-1), i=numtheory[divisors](n)) end:

seq(print(A200583_row(i)), i=1..12);

MATHEMATICA

A198060[m_, n_] := Sum[Sum[Sum[(-1)^(j+i)*Binomial[i, j]*Binomial[n, k]^(m+1)*(n+1)^j*(k+1)^(m-j)/(k+1)^m, {i, 0, m}], {j, 0, m}], {k, 0, n}]; row[n_] := Table[A198060[d-1, n/d-1], {d, Divisors[n]}]; Table[row[n], {n, 1, 20}] // Flatten (* Jean-Fran├žois Alcover, Feb 25 2014, after Maple *)

CROSSREFS

Cf. A198060, A199932, A200062.

Sequence in context: A307683 A248058 A072345 * A115120 A147373 A147441

Adjacent sequences:  A200580 A200581 A200582 * A200584 A200585 A200586

KEYWORD

nonn,tabf

AUTHOR

Peter Luschny, Nov 20 2011

STATUS

approved

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Last modified May 28 01:34 EDT 2020. Contains 334671 sequences. (Running on oeis4.)