A195572 Numerators b(n) of Pythagorean approximations b(n)/a(n) to 1/5.

0, 9, 11, 20, 819, 1221, 2020, 83629, 124431, 206040, 8529239, 12690841, 21014040, 869898849, 1294341251, 2143226060, 88721153259, 132010116861, 218588044060, 9048687733669, 13463737578471, 22293837268080, 922877427680879

Offset

1,2

Comments

See A195500 for discussion and list of related sequences; see A195571 for Mathematica program.

Conjecture: satisfies a linear recurrence having signature (0, 0, 101, 0, 0, 101, 0, 0, -1). - Harvey P. Dale, Jun 13 2025

Links

Table of n, a(n) for n=1..23.

Formula

Empirical g.f.: -x^2*(x^7-x^6-110*x^4+90*x^3-20*x^2-11*x-9) / (x^9-101*x^6-101*x^3+1). - Colin Barker, Jun 04 2015

Crossrefs

Cf. A195500, A195571, A195573.

Sequence in context: A372242 A284295 A284294 * A046259 A258452 A299250

Adjacent sequences: A195569 A195570 A195571 * A195573 A195574 A195575

Keyword

nonn

Author

Clark Kimberling, Sep 21 2011

Status

approved