0,2

C. Pickover, Mazes for the Mind, St. Martin's Press, NY, 1992, p. 350-351.

E = Sum[A081368[n]/10^a(n),{n,1,Length}]; Solve for a(n).

Clear[a, n];

a = {2, 71, 828, 1828, 45904, 5235360, 2874713, 52662497, 757247093, 6999595749, 66967627724, 76630353547,

5945713821785, 25166427427466, 391932003059921, 8174135966290435, 72900334295260595, 630738132328627943};

b = Table[Length[IntegerDigits[a[[n]]]], {n, 1, Length[a]}];

c = Table[Sum[b[[m]], {m, 1, n}] - 1, {n, 1, Length[b]}] Sum[a[[n]]/10^(c[[n]]), {n, 1, Length[a]}];

N[% - E, 100]

Sequence in context: A048093 A024669 A006482 this_sequence A139423 A026053 A011905

Adjacent sequences: A152885 A152886 A152887 this_sequence A152889 A152890 A152891

nonn

Roger L. Bagula (rlbagulatftn(AT)yahoo.com), Dec 14 2008