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A202408 Denominator of series coefficients for Archimedes' spiral which transforms into Galileo's spiral. 1
1, 2, 32, 768, 49152, 1, 56623104, 3170893824, 541165879296, 175337744891904, 28054039182704640, 29389945810452480, 2844006276185865584640, 147888326361665010401280, 25765432859454526256578560, 83480002464632665071314534400 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Numerators are listed in A202407 which is the main entry for these sequences.

LINKS

Table of n, a(n) for n=0..15.

MATHEMATICA

km = 16; a[0] = 0; r[t_] = Sum[a[k] t^(2 k), {k, 0, km}]; coes = CoefficientList[Series[r'[t]^2 + r[t]^2 - t^2 , {t, 0, 2 km}], t] // Union // Rest; Table[a[k], {k, 0, km}] /. Solve[Thread[coes == 0] ] // Last // Most // Denominator (* Jean-Fran├žois Alcover, Jan 18 2013 *)

CROSSREFS

Sequence in context: A304860 A198599 A009517 * A069182 A012233 A321712

Adjacent sequences:  A202405 A202406 A202407 * A202409 A202410 A202411

KEYWORD

nonn,frac

AUTHOR

Mikhail Gaichenkov, Dec 19 2011

EXTENSIONS

Corrected and extended by Max Alekseyev, Dec 19 2011

STATUS

approved

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Last modified February 17 02:22 EST 2020. Contains 331976 sequences. (Running on oeis4.)