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 A036447 #24 Jan 03 2020 04:34:20 %S A036447 1,2,4,8,61,221,244,884,8671,24371,24784,86594,881371,2472671,2435494, %T A036447 8890784,86518771,245730371,247064194,883821494,8892467671, %U A036447 24353948771,24579870784,86514795194,883095920371,2470481916671,2433383690494 %N A036447 Double and reverse digits. %H A036447 Harvey P. Dale, <a href="/A036447/b036447.txt">Table of n, a(n) for n = 0..1000</a> %H A036447 Nick Hobson, <a href="/A036447/a036447.py.txt">Python program for this sequence</a> %F A036447 a(n+1) = A004093(a(n)). - _Reinhard Zumkeller_, Feb 09 2012 %F A036447 Conjecture: a(n)^(1/n) tends to sqrt(10). - _Vaclav Kotesovec_, Jan 03 2020 %t A036447 NestList[ FromDigits[ Reverse[ IntegerDigits[ 2# ] ] ] &, 1, 27 ] %t A036447 NestList[IntegerReverse[2#]&,1,30] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Jun 18 2017 *) %o A036447 (Haskell) %o A036447 a036447 n = a036447_list !! n %o A036447 a036447_list = iterate a004093 1 -- _Reinhard Zumkeller_, Feb 09 2012 %Y A036447 Cf. A004086, A004093. %Y A036447 The following are parallel families: A000079 (2^n), A004094 (2^n reversed), A028909 (2^n sorted up), A028910 (2^n sorted down), A036447 (double and reverse), A057615 (double and sort up), A263451 (double and sort down); A000244 (3^n), A004167 (3^n reversed), A321540 (3^n sorted up), A321539 (3^n sorted down), A163632 (triple and reverse), A321542 (triple and sort up), A321541 (triple and sort down). %Y A036447 Cf. A132064, A045539, A132078, A132114, A132113, A133361. %K A036447 nonn,base,easy,nice %O A036447 0,2 %A A036447 _Rodolfo Kurchan_ %E A036447 More terms from Larry Reeves (larryr(AT)acm.org), Mar 31 2000