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A309907 a(n) is the square of the number consisting of one 1 and n 3's: (133...3)^2. 3
1, 169, 17689, 1776889, 177768889, 17777688889, 1777776888889, 177777768888889, 17777777688888889, 1777777776888888889, 177777777768888888889, 17777777777688888888889, 1777777777776888888888889, 177777777777768888888888889, 17777777777777688888888888889 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
COMMENTS
All terms are zeroless (elements of A052382).
LINKS
FORMULA
G.f.: -(40*x^2+58*x+1)/((x-1)*(100*x-1)*(10*x-1)).
a(n) = A097166(n)^2 = ((4*10^n-1)/3)^2. - Seiichi Manyama, Aug 23 2019
MAPLE
a:= n-> parse(cat(1, 3$n))^2:
seq(a(n), n=0..18);
PROG
(PARI) {a(n) = ((4*10^n-1)/3)^2} \\ Seiichi Manyama, Aug 23 2019
CROSSREFS
Sequence in context: A264276 A231769 A069297 * A264222 A051477 A227692
KEYWORD
nonn,base,easy
AUTHOR
Alois P. Heinz, Aug 21 2019
STATUS
approved

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Last modified April 19 02:28 EDT 2024. Contains 371782 sequences. (Running on oeis4.)