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A240733 Floor(6^n/(2+2*cos(Pi/9))^n). 10
1, 1, 2, 3, 5, 8, 13, 21, 32, 50, 78, 121, 187, 289, 448, 693, 1072, 1658, 2564, 3966, 6134, 9487, 14673, 22695, 35101, 54288, 83964, 129862, 200850, 310643, 480452, 743085, 1149282, 1777523, 2749182, 4251987, 6576279, 10171116, 15731022, 24330178, 37629950 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,3
COMMENTS
a(n) is the perimeter (rounded down) of a nonaflake after n iterations, let a(0) = 1. The total number of sides is 9*A000400(n). The total number of holes is A002452(n). 2*cos(Pi/9) = 1.87938524... = diagonal b of nonagon (see comments in A123609).
LINKS
Wikipedia, n-flake
MAPLE
A240733:=n->floor(6^n/(2+2*cos(Pi/9))^n); seq(A240733(n), n=0..50); # Wesley Ivan Hurt, Apr 12 2014
MATHEMATICA
Table[Floor[6^n/(2 + 2*Cos[Pi/9])^n], {n, 0, 50}] (* Wesley Ivan Hurt, Apr 12 2014 *)
PROG
(PARI) {a(n)=floor(6^n/(2+2*cos(Pi/9))^n)}
for (n=0, 100, print1(a(n), ", "))
CROSSREFS
Cf. A000400, A002452, A123609, A240523 (pentaflake), A240671 (heptaflake), A240572 (octaflake), A240733 (nonaflake), A240734 (decaflake), A240735 (dodecaflake).
Sequence in context: A065124 A048817 A011185 * A283936 A278800 A334738
KEYWORD
nonn,easy
AUTHOR
Kival Ngaokrajang, Apr 11 2014
STATUS
approved

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Last modified February 21 02:30 EST 2024. Contains 370219 sequences. (Running on oeis4.)