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A109057 To compute a(n) we first write down 5^n 1's in a row. Each row takes the rightmost 5th 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 5th part. The single element in the last row is a(n). 5
1, 1, 5, 115, 12885, 7173370, 19940684251, 277078842941900, 19249144351745111125 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..8.

EXAMPLE

For example, for n=3 the array, from 2nd row, follows:

1..2..3.....14..15..16..17..18..19..20..21..22..23..24..25

........................................21..43..66..90.115

.......................................................115

Therefore a(3)=115.

MAPLE

proc(n::nonnegint) local f, a; if n=0 or n=1 then return 1; end if; f:=L->[seq(add(L[i], i=4*nops(L)/5+1..j), j=4*nops(L)/5+1..nops(L))]; a:=f([seq(1, j=1..5^n)]); while nops(a)>5 do a:=f(a) end do; a[5]; end proc;

CROSSREFS

Cf. A107354, A109055, A109056, A109058, A109059, A109060, A109061, A109062.

Sequence in context: A208959 A209053 A255884 * A245105 A080988 A230338

Adjacent sequences:  A109054 A109055 A109056 * A109058 A109059 A109060

KEYWORD

nonn

AUTHOR

Augustine O. Munagi, Jun 17 2005

STATUS

approved

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Last modified May 28 04:00 EDT 2020. Contains 334671 sequences. (Running on oeis4.)