A068623 a(1) = 8; a(n+1) = smallest triangular number > a(n) formed by adding at least one digit to a(n).

8, 28, 528, 18528, 184528, 18045028, 1800450028, 180004500028, 18000045000028, 1800000450000028, 180000004500000028, 18000000045000000028, 1800000000450000000028, 180000000004500000000028

Offset

1,1

Links

Table of n, a(n) for n=1..14.

Formula

For n>=5, a(n) = 18*10^(2*n-6) + 45*10^(n-3) + 28 [From Max Alekseyev, Apr 25 2009]

Crossrefs

Cf. A068618, A068619, A068621, A068622, A068624.

Sequence in context: A228281 A146977 A374138 * A361585 A297885 A298290

Adjacent sequences: A068620 A068621 A068622 * A068624 A068625 A068626

Keyword

base,nonn

Author

Amarnath Murthy, Feb 25 2002

Extensions

3 more terms from Ray G. Opao, Dec 14 2004

Extended by Max Alekseyev, Apr 25 2009

Status

approved