OFFSET
1,3
EXAMPLE
0; 1,2; 12,13,23; 123,124,134,234; 1234,1235,1245,1345,2345; 12345,12346, ...
MAPLE
conca := proc(S) local resul, d, i ; resul := 0 ; for i from 1 to nops(S) do d := ilog10(op(i, S))+1 ; resul := resul*10^d+op(i, S) ; od ; resul ; end: A081539 := proc(row) local a, p, i; if row =1 then RETURN([0]) ; fi ; a := [] ; p := [seq(i, i=1..row)] ; for i from 1 to row do a := [op(a), conca(subsop(i=NULL, p))] ; od: sort(a)[1..row] ; end: for n from 1 to 10 do op(A081539(n)) ; od ; # R. J. Mathar, Jul 15 2007
CROSSREFS
KEYWORD
AUTHOR
Amarnath Murthy, Mar 29 2003
EXTENSIONS
More terms from R. J. Mathar, Jul 15 2007
Edited by Charles R Greathouse IV, Apr 30 2010
STATUS
approved