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 A266569 #32 May 06 2016 06:52:02 %S A266569 1,5,30,13,68,42,64,29,132,88,119,66,154,92,132,61,248,168,217,128, %T A266569 261,163,221,114,322,206,273,148,326,192,268,125,468,316,401,240,463, %U A266569 293,387,208,533,345,448,251,519,313,425,210,646,422,543,310,623,381,511 %N A266569 a(1) = 1; thereafter a(2k) = 4k + a(k); a(2k+1) = k + a(4k+4). %H A266569 Daniel Suteu, <a href="/A266569/b266569.txt">Table of n, a(n) for n = 1..10000</a> %H A266569 Daniel Suteu, <a href="/A266569/a266569.txt">Table of n, a(n) for n = 1..100000</a> %e A266569 For n=2, a(2) = 4 + a(1) = 5. %e A266569 For n=3: %e A266569 a(3) = 1 + a(8); %e A266569 a(8) = 2*8 + a(8/2) = 16 + a(4); %e A266569 a(4) = 2*4 + a(4/2) = 8 + a(2) = 13; %e A266569 a(8) = 18+13 = 29; %e A266569 a(3) = 1 + 29 = 30. %p A266569 A266569 := proc(n) %p A266569 option remember; %p A266569 local k; %p A266569 if n = 1 then %p A266569 1; %p A266569 elif type(n,'even') then %p A266569 2*n+procname(n/2) ; %p A266569 else %p A266569 k := (n-1)/2 ; %p A266569 k+procname(4*k+4) ; %p A266569 end if; %p A266569 end proc: %p A266569 seq(A266569(n),n=1..100) ; # _R. J. Mathar_, May 06 2016 %t A266569 a[1] = 1; a[n_] := a[n] = If[EvenQ@ n, 2 n + a[n/2], (n - 1)/2 + a[2 (n + 1)]]; Array[a, 55] (* _Michael De Vlieger_, Jan 02 2016 *) %o A266569 (Sidef) %o A266569 func a((1)) { 1 } %o A266569 func a(n {.is_even}) is cached { 2*n + a(n/2) } %o A266569 func a(n {.is_odd }) is cached { (n-1)/2 + a(2*(n + 1)) } %o A266569 1000.times { |n| say a(n) } %Y A266569 Records (high water marks): A270811, A270812. %Y A266569 Cf. A270814, A271473, A271478, A271479. %K A266569 nonn,easy %O A266569 1,2 %A A266569 _Daniel Suteu_, Jan 01 2016