A069669
Smallest n-digit triangular number with maximum digit sum.
Original entry on oeis.org
6, 78, 496, 8778, 58996, 887778, 5897895, 88877778, 686999778, 9876799878, 89996788896, 777887999778, 7798988788878, 77779987999896, 589598998999878, 7898898998885986, 78999997699698778, 999699998689998991
Offset: 1
More terms from Larry Reeves (larryr(AT)acm.org), Oct 15 2003
A069670
Largest n-digit triangular number with maximum digit sum.
Original entry on oeis.org
6, 78, 946, 8778, 58996, 998991, 9979278, 98989485, 886899786, 9998888991, 89996788896, 999998497578, 9869988988965, 99989985868878, 988895779999896, 9999678588989986, 99889886986899778, 999699998689998991
Offset: 1
More terms from Larry Reeves (larryr(AT)acm.org), Oct 15 2003
A069671
Smallest n-digit triangular number with minimum digit sum.
Original entry on oeis.org
1, 10, 120, 2211, 10011, 112101, 2001000, 10006101, 200010000, 1210000221, 20000100000, 210010000005, 2000001000000, 32000004000000, 200000010000000, 3200000040000000, 20000000100000000, 320000000400000000, 2000000001000000000, 32000000004000000000
Offset: 1
A069672
Largest n-digit triangular number with minimum digit sum.
Original entry on oeis.org
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
Offset: 1
Cf.
A069661,
A069662,
A069663,
A069664,
A069665,
A069666,
A069667,
A069668,
A069669,
A069670,
A069671.
-
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
Showing 1-4 of 4 results.
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