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A195503
Numerators b(n) of Pythagorean approximations b(n)/a(n) to sqrt(3).
5
4, 15, 56, 209, 780, 2911, 10864, 40545, 151316, 564719, 2107560, 7865521, 29354524, 109552575, 408855776, 1525870529, 5694626340, 21252634831, 79315912984, 296011017105, 1104728155436, 4122901604639, 15386878263120, 57424611447841
OFFSET
1,1
COMMENTS
See A195500 for discussion and list of related sequences; see A195499 for Mathematica program.
Essentially the same as A001353, A106707, A125905 and likely also A010905. - R. J. Mathar, Sep 21 2011
If started 1, 4, 15, 56, ...., denominators a(n) of Pythagorean approximations b(n)/a(n) to sqrt(1/3). - Clark Kimberling, Sep 22 2011
FORMULA
a(n) = A001353(n+1). - R. J. Mathar, Sep 21 2011
Empirical G.f.: x*(4-x)/(1-4*x+x^2). - Colin Barker, Jan 04 2012
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Sep 20 2011
STATUS
approved