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 A067358 #26 Apr 22 2024 09:41:16
%S A067358 0,12,120,-828,-28560,-145668,3369960,58317492,13651680,-9719139348,
%T A067358 -99498527400,647549275812,23290743888720,123471611274972,
%U A067358 -2701419604443960,-47880898349909868,-22269070348069440,7869181117654073292,82455284065364468280,-505338768229893703548
%N A067358 Imaginary part of (5+12i)^n.
%C A067358 Also 13^n sin(2n arctan(2/3)) or numerator of tan(2n arctan(2/3)).
%C A067358 Note that a(n), A067359(n) and 13^n are primitive Pythagorean triples with hypotenuse 13^n.
%D A067358 Steven R. Finch, Mathematical Constants, Cambridge, 2003, pp. 430-433.
%H A067358 J. M. Borwein and R. Girgensohn, <a href="http://dx.doi.org/10.4153/CJM-1995-013-4">Addition theorems and binary expansions</a>, Canadian J. Math. 47 (1995) 262-273.
%H A067358 E. Eckert, <a href="http://www.jstor.org/stable/2690291">The group of primitive Pythagorean triangles</a>, Mathematics Magazine 57 (1984) 22-27.
%H A067358 Steven R. Finch, <a href="http://www.people.fas.harvard.edu/~sfinch/constant/plff/plff.html">Plouffe's Constant</a> [Broken link]
%H A067358 Steven R. Finch, <a href="http://web.archive.org/web/20010624104257/http://www.mathsoft.com/asolve/constant/plff/plff.html">Plouffe's Constant</a> [From the Wayback machine]
%H A067358 Simon Plouffe, <a href="https://cs.uwaterloo.ca/journals/JIS/compass.html">The Computation of Certain Numbers Using a Ruler and Compass</a>, J. Integer Seqs. Vol. 1 (1998), #98.1.3.
%H A067358 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (10,-169).
%F A067358 G.f.: 12*x/(1-10*x+169*x^2). a(n)=10*a(n-1)-169*a(n-2). - _Michael Somos_, Jun 27 2002
%p A067358 a[1] := 12/5; for n from 1 to 40 do a[n+1] := (12/5+a[n])/(1-12/5*a[n]):od: seq(abs(numer(a[n])), n=1..40);# a[n]=tan(2n arctan(2/3))
%t A067358 Im[(5 + 12*I)^Range[0, 24]] (* or *)
%t A067358 LinearRecurrence[{10, -169}, {0, 12}, 25] (* _Paolo Xausa_, Apr 22 2024 *)
%o A067358 (PARI) a(n)=imag((5+12*I)^n)
%Y A067358 Cf. A067359 (13^n cos(2n arctan(2/3))).
%Y A067358 Cf. A066770, A066771, A067360, A067361, A020888, A014498, A020892.
%K A067358 sign,easy,frac
%O A067358 0,2
%A A067358 Barbara Haas Margolius, (b.margolius(AT)csuohio.edu), Jan 17 2002
%E A067358 Better description from _Michael Somos_, Jun 27 2002