A081540 Sum of terms in row n of A081539.

0, 3, 48, 615, 7404, 86415, 987648, 11111103, 123456780, 12469134879, 1259259166920, 127160484583143, 12839505247415568, 1296296203651668195, 130864188256177941024, 13209875614718906234055, 1333333240382001836547288, 134567891929211304968880723, 13580245982022242628303234360

Offset

1,2

Links

Table of n, a(n) for n=1..19.

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: A081540 := proc(n) local r ; r := A081539(n) ; add(r[i], i=1..n) ; end: seq(A081540(n), n=1..20) ; # R. J. Mathar, Jul 15 2007

Crossrefs

Cf. A081539.

Sequence in context: A335178 A260347 A140650 * A294829 A264730 A024042

Adjacent sequences: A081537 A081538 A081539 * A081541 A081542 A081543

Keyword

nonn,base

Author

Amarnath Murthy, Mar 29 2003

Extensions

Corrected and extended by R. J. Mathar, Jul 15 2007

Status

approved