A062102 Numbers n such that no substring is a triangular number.

2, 4, 5, 7, 8, 9, 22, 24, 25, 27, 29, 42, 44, 47, 48, 49, 52, 54, 57, 58, 59, 72, 74, 75, 77, 79, 82, 84, 85, 87, 88, 89, 92, 94, 95, 97, 98, 99, 222, 224, 225, 227, 229, 242, 244, 247, 248, 249, 252, 254, 257, 258, 259, 272, 274, 275, 277, 279, 292, 294, 295, 297

Offset

1,1

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Example

23 is not included because 3 is triangular

Maple

istri:= n -> issqr(1+8*n):
filter:= proc(n) local d, i, j, v;
   for i from 0 do
     v:= floor(n/10^i);
     if v = 0 then return true fi;
     if istri(v) then return false fi;
     for j from ilog10(v) to 1 by -1 do
       if istri(v mod 10^j) then return false fi;
     od
    od
end proc:
select(filter, [$1..1000]); # Robert Israel, Aug 18 2024

Crossrefs

Sequence in context: A190852 A005839 A254792 * A092289 A079358 A184014

Adjacent sequences: A062099 A062100 A062101 * A062103 A062104 A062105

Keyword

base,easy,nonn

Author

Erich Friedman, Jun 28 2001

Status

approved