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Search: id:A109056
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| A109056 |
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To compute a(n) we first write down 4^n 1's in a row. Each row takes the rightmost 4th part of the previous row and each element in it equals sum of the elements of the previous row starting with the first of the rightmost 4th part. The single element in the last row is a(n). |
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+0
8
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| 1, 1, 4, 58, 3236, 713727, 627642640, 2205897096672, 31004442653082720, 1743005531132374350208
(list; graph; listen)
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OFFSET
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0,3
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EXAMPLE
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For example, for n=3 the array looks like this:
1..1.....1..1..1..1..1..1..1..1..1..1..1..1..1..1..1..1..1
............1..2..3..4..5..6..7..8..9.10.11.12.13.14.15.16
...............................................13.27.42.58
........................................................58
Therefore a(4)=58.
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MAPLE
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proc(n::nonnegint) local f, a; if n=0 or n=1 then return 1; end if; f:=L->[seq(add(L[i], i=3*nops(L)/4+1..j), j=3*nops(L)/4+1..nops(L))]; a:=f([seq(1, j=1..4^n)]); while nops(a)>4 do a:=f(a) end do; a[4]; end proc;
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CROSSREFS
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Sequence in context: A108148 A099348 A155668 this_sequence A155204 A144992 A037066
Adjacent sequences: A109053 A109054 A109055 this_sequence A109057 A109058 A109059
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KEYWORD
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nonn
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AUTHOR
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A. O. Munagi (amunagi(AT)yahoo.com), Jun 17 2005
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