A069697 Triangular numbers with internal digits 5.

0, 1, 3, 6, 10, 15, 21, 28, 36, 45, 55, 66, 78, 91, 153, 253, 351, 2556, 6555

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]] == {5}, Print[n(n + 1)/2]], {n, 14, 2 10^6}]

Crossrefs

Cf. A069675 to A069684, A069693 to A069700.

Sequence in context: A069693 A069694 A069695 * A069699 A213516 A078254

Adjacent sequences: A069694 A069695 A069696 * A069698 A069699 A069700

Keyword

nonn,base,fini,full

Author

Amarnath Murthy, Apr 06 2002

Extensions

Extended by Robert G. Wilson v, Apr 07 2002

Status

approved