A155105 - OEIS

A155105

Numbers appearing the third column of A155103.

1, 4, 28, 364, 9100, 445900, 43252300

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OFFSET

1,2

LINKS

MAPLE

A155102 := proc(n, k) if n = k then 1 ; elif n =2*k then -k-1 ; else 0; end if; end proc:

A155103 := proc(amx) a := array(1..amx, 1..amx) ; a[1, 1] := 1/A155102(1, 1) ;

for r from 1 to amx do

for c from 1 to r-1 do a[c, r] := 0 ; end do:

a[r, r] := 1/A155102(r, r) ;

for c from r-1 to 1 by -1 do a[r, c] := -add(a[cp, c]*A155102(r, cp), cp=c..r-1)/A155102(r, r) ;

if c = 3 and a[r, c] <> 0 then print( a[r, c]) ; end if;

end do:

return ;

end proc:

A155103(290) ; # R. J. Mathar, Dec 07 2010

CROSSREFS

KEYWORD

nonn,more

AUTHOR

Mats Granvik, Jan 20 2009

EXTENSIONS

Two more terms from R. J. Mathar, Dec 07 2010

STATUS

approved