A069694 Triangular numbers with internal digits 2.

0, 1, 3, 6, 10, 15, 21, 28, 36, 45, 55, 66, 78, 91, 120, 325, 528, 820, 1225

Offset

1,3

Comments

For proof of finiteness see A069693.

Links

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

Mathematica

Do[ If[ Union[ Drop[ RotateLeft[ IntegerDigits[n(n + 1)/2]], -2]] == {2}, Print[n(n + 1)/2]], {n, 14, 2 10^6}]

Crossrefs

Cf. A069675 to A069684, A069693 to A069700.

Sequence in context: A077366 A077368 A069693 * A069695 A069697 A069699

Adjacent sequences: A069691 A069692 A069693 * A069695 A069696 A069697

Keyword

fini,full,nonn,base

Author

Amarnath Murthy, Apr 06 2002

Status

approved