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 A160469 #8 Apr 24 2018 22:44:05 %S A160469 1,1,2,17,62,1382,21844,929569,6404582,443861162,18888466084, %T A160469 1936767361654,58870668456604,8374643517010684,689005380505609448, %U A160469 129848163681107301953,1736640792209901647222,418781231495293038913922 %N A160469 The left hand column of the triangle A160468. %C A160469 Resembles A002430, the numerators of the Taylor series for tan(x). The first difference occurs at a(12). (Its resemblance to this sequence led to the conjecture A160469(n) = A002430(n)*A089170(n-1).) %F A160469 a(n) = A002430(n)*A089170(n-1) with A002430 (n) = numer((-1)^(n-1)*2^(2*n)*(2^(2*n)-1)* bernoulli(2*n)/(2*n)!) and A089170 (n-1) = numer(2*bernoulli(2*n)* (4^n-1)/(2*n))/ numer((4^n-1)*bernoulli(2*n)/(2*n)!) for n = 1, 2, 3, .... %Y A160469 Equals the first left hand column of A160468. %Y A160469 Equals A002430(n)*A089170(n-1). %Y A160469 Equals (A002430(n)/A036279(n))*(A117972(n)/A000265(n)). %Y A160469 Equals A048896(n-1)*A002425(n). %Y A160469 Cf. A156769 (which resembles the denominators of the Taylor series for tan(x)). %K A160469 easy,nonn %O A160469 1,3 %A A160469 _Johannes W. Meijer_, May 24 2009