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A069672 Largest n-digit triangular number with minimum digit sum. 0
1, 10, 300, 3003, 20100, 112101, 2001000, 33020001, 200010000, 3200120001, 20000100000, 320001200001, 2000001000000, 32000012000001, 200000010000000, 3200000120000001, 20000000100000000, 320000001200000001, 2000000001000000000, 32000000012000000001, 200000000010000000000, 3200000000120000000001, 20000000000100000000000, 320000000001200000000001, 2000000000001000000000000, 32000000000012000000000001, 200000000000010000000000000, 3200000000000120000000000001, 20000000000000100000000000000, 320000000000001200000000000001 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Does the obvious pattern continue? - Vladeta Jovovic, Apr 07 2002

LINKS

Table of n, a(n) for n=1..30.

MAPLE

F:= proc(d)

local s, P, nP, S, x, bestx;

bestx:= 0;

for s in [1, 3, 6, 9] do

  for P in map(op @combinat:-permute, combinat:-partition(s)) do

    nP:= nops(P);

    for S in map(t -> [d-1, op(t)], combinat:-choose([$0..d-2], nP-1)) do

      x:= add(P[i]*10^S[i], i=1..nP);

      if x > bestx and issqr(1+8*x) then bestx:= x fi;

    od;

  od;

  if bestx > 0 then return bestx fi;

od;

end proc:

seq(F(d), d=1..30); # Robert Israel, May 25 2016

CROSSREFS

Cf. A069661, A069662, A069663, A069664, A069665, A069666, A069667, A069668, A069669, A069670, A069671.

Sequence in context: A217487 A173479 A173478 * A129005 A162729 A278037

Adjacent sequences:  A069669 A069670 A069671 * A069673 A069674 A069675

KEYWORD

nonn,base

AUTHOR

Amarnath Murthy, Apr 06 2002

EXTENSIONS

More terms from Vladeta Jovovic, Apr 07 2002

a(15)..a(30) from Robert Israel, May 25 2016

STATUS

approved

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Last modified August 3 20:08 EDT 2020. Contains 336201 sequences. (Running on oeis4.)