A205493 - OEIS

A205493

Third row or column of table A205497.

1, 14, 109, 623, 2951, 12331, 47191, 169416, 579889, 1914226, 6144668, 19298724, 59579803, 181448918, 546629054, 1632497850, 4841448042, 14277423006, 41912838982, 122587133760, 357476552161, 1039922075888, 3019280091491, 8752184436454, 25337900299765

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,2

COMMENTS

See A205497 regarding association of this sequence with generating functions for the rows of the tabular form of A050446.

LINKS

Table of n, a(n) for n=0..24.

L. E. Jeffery, Unit-primitive matrices

FORMULA

Conjecture 1. a(n) = M_{n,3} = M_{3,n}, where M = A205497.

Conjecture 2. Let w=2*cos(Pi/9). Then lim_{n->oo} a(n+1)/a(n) = w^3-2*w = spectral radius of the 4 X 4 unit-primitive matrix (see [Jeffery]) A_{9,3} = [0,0,0,1; 0,0,1,1; 0,1,1,1; 1,1,1,1].

PROG

(Python) # See program in A205497.

CROSSREFS

Cf. A205497, A050446, A050447.

Sequence in context: A020327 A039629 A349296 * A074886 A294445 A036395

Adjacent sequences: A205490 A205491 A205492 * A205494 A205495 A205496

KEYWORD

nonn

AUTHOR

L. Edson Jeffery, Jan 28 2012

EXTENSIONS

a(24) and changed title from Hugo Pfoertner, Jan 05 2020

STATUS

approved