A081541 Triangle read by rows: the n-th row contains n numbers sorted in decreasing value, each build by dropping a different number from the sequence [n,n-1,n-2,....,1] and concatenating the n-1 others. By definition the first row contains 0.

0, 2, 1, 32, 31, 21, 432, 431, 421, 321, 5432, 5431, 5421, 5321, 4321, 65432, 65431, 65421, 65321, 64321, 54321, 765432, 765431, 765421, 765321, 764321, 754321, 654321, 8765432, 8765431, 8765421, 8765321, 8764321, 8754321, 8654321, 7654321

Offset

1,2

Links

Harvey P. Dale, Table of n, a(n) for n = 1..10000

Example

Triangle begins:
0;
2,1;
32,31,21;
432,431,421,321;
5432,5431,5421,5321,4321;
65432,65431,...

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: A081541 := proc(row) local a, p, i; if row =1 then RETURN([0]) ; fi ; a := [] ; p := [seq(row+1-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: seq(op(A081541(n)), n=1..10) ; # R. J. Mathar, Jul 15 2007

Mathematica

Table[Reverse[FromDigits/@Table[Drop[Range[k, 1, -1], {n}], {n, 1, k}]], {k, 8}]//Flatten (* Harvey P. Dale, Aug 27 2016 *)

Crossrefs

Cf. A081539, A081540, A081542.

Sequence in context: A074011 A054235 A016547 * A344105 A323751 A113465

Adjacent sequences: A081538 A081539 A081540 * A081542 A081543 A081544

Keyword

base,nonn,tabl

Author

Amarnath Murthy, Mar 29 2003

Extensions

More terms from R. J. Mathar, Jul 15 2007

Status

approved