%I A128507
%S A128507 1,27,3375,1157625,31255875,41601569625,91398648466125,91398648466125,
%T A128507 449041559914072125,3079976059450620705375,439996579921517243625,
%U A128507 5353438387905100303185375,669179798488137537898171875
%N A128507 Denominators of partial sums for a series for 3*sqrt(2)*(Pi^3)/2^7.
%C A128507 The numerators are given in A128506.
%C A128507 See the comments and the W. Lang link under A128506.
%F A128507 a(n)=denominator(r(n)) with the rationals r(n):=sum(S(2*k,sqrt(2))/(2*k+1)^3,
               k=0..n) with Chebyshev's S-Polynomials S(2*k,sqrt(2))=[1,1,-1,-1] 
               periodic sequence with period 4. See A057077.
%e A128507 Rationals r(n): [1, 28/27, 3473/3375, 1187864/1157625, 32115203/31255875,
               ...].
%e A128507 3*sqrt(2)*(Pi^3)/2^7 = +1/1^3 +1/3^3 -1/5^3 -1/7^3 +1/9^3 +1/11^3 -1/
               13^3 -1/15^3 ++--
%Y A128507 Sequence in context: A132645 A017559 A069076 this_sequence A166750 A046367 
               A059795
%Y A128507 Adjacent sequences: A128504 A128505 A128506 this_sequence A128508 A128509 
               A128510
%K A128507 nonn,frac,easy
%O A128507 0,2
%A A128507 Wolfdieter Lang (wolfdieter.lang(AT)physik.uni-karlsruhe.de) Apr 04 2007