A241787 Triangular numbers which have one or more occurrences of exactly four different digits.

1035, 1275, 1326, 1378, 1485, 1540, 1596, 1653, 1830, 1953, 2016, 2145, 2346, 2415, 2485, 2701, 2850, 3081, 3160, 3240, 3486, 3570, 3741, 3916, 4095, 4186, 4278, 4371, 4560, 4753, 4851, 4950, 5460, 5671, 6105, 6328, 6903, 7021, 7140, 7260, 7381, 7503, 8256

Offset: 1

Author

Colin Barker, Apr 28 2014

Keywords

• nonn
• base

Comments

The first term having a repeated digit is 10153.

Links

• Colin Barker, Table of n, a(n) for n = 1..2000

Crossrefs

Cf. A045914, A062691, A162304, A241788, A241789, A241790, A241791, A241792, A241812.

Cf. A000217.

Programs

Mathematica

Select[Accumulate[Range[200]],Count[DigitCount[#],0]==6&] (* Harvey P. Dale, Jun 29 2022 *)

PARI

s=[]; for(n=0, 300, if(#vecsort(eval(Vec(Str(n*(n+1)/2))), , 8)==4, s=concat(s, n*(n+1)/2))); s