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A209269 a(1) = 1 and, for n >= 2, a(n) is the least integer such that the numerator of the continued fraction [a(1),a(2),...,a(n)] is a perfect square. 0
1, 3, 2, 5, 43, 522, 1104509 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..7.

FORMULA

a(n) = (A086541(n) - A086541(n-2)) / A086541(n-1) (n >= 3). - Hiroaki Yamanouchi, Oct 03 2014

PROG

(PARI) v=[1]; for(k=1, 6, m=1; while(issquare(contfracpnqn(concat(v, [m]))[1, 1])==0, m++); v=concat(v, [m])); a(n)=if(n<2, 1, v[n]);

CROSSREFS

Cf. A086541

Sequence in context: A005265 A005266 A005267 * A244823 A286157 A016460

Adjacent sequences:  A209266 A209267 A209268 * A209270 A209271 A209272

KEYWORD

nonn,more

AUTHOR

Benoit Cloitre, Jan 15 2013

STATUS

approved

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Last modified August 4 07:49 EDT 2021. Contains 346445 sequences. (Running on oeis4.)