This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A138706 #21 Apr 14 2023 10:54:10
%S A138706 1,6,30,42,30,18,37,7,28,96,559,6210,86617,1425523,27298263,601580913,
%T A138706 15116315788,429614643067,13711655205344,488332318973599,
%U A138706 19296579341940107,841693047573684421,40338071854059455479,2115074863808199160579,120866265222965259346062
%N A138706 a(n) is the sum of the terms in the continued fraction expansion of the absolute value of B_{2n}, the (2n)-th Bernoulli number.
%F A138706 a(n) = A138703(2*n). - _R. J. Mathar_, Jul 20 2009
%e A138706 The 12th Bernoulli number is -691/2730. Now 691/2730 has the continued fraction 0 + 1/(3 + 1/(1 + 1/(19 + 1/(3 + 1/11)))). So a(6) = 0 + 3 + 1 + 19 + 3 + 11 = 37.
%p A138706 A138704row := proc(n) local B; B := abs(bernoulli(2*n)) ; numtheory[cfrac](B,20,'quotients') ; end: A138706 := proc(n) add(c,c=A138704row(n)) ; end: seq(op(A138706(n)),n=0..30) ; # _R. J. Mathar_, Jul 20 2009
%t A138706 Table[Total[ContinuedFraction[Abs[BernoulliB[2n]]]],{n,0,25}] (* _Harvey P. Dale_, Feb 23 2012 *)
%o A138706 (PARI) a(n) = vecsum(contfrac(abs(bernfrac(2*n)))); \\ _Jinyuan Wang_, Aug 07 2021
%o A138706 (Python)
%o A138706 from sympy import continued_fraction, bernoulli
%o A138706 def A138706(n): return sum(continued_fraction(abs(bernoulli(n<<1)))) # _Chai Wah Wu_, Apr 14 2023
%Y A138706 Cf. A027641/A027642, A138703, A138704, A138705.
%K A138706 nonn
%O A138706 0,2
%A A138706 _Leroy Quet_, Mar 26 2008
%E A138706 a(7)-a(22) from _R. J. Mathar_, Jul 20 2009
%E A138706 More terms from _Jinyuan Wang_, Aug 07 2021