A068623 - OEIS

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

(list; graph; refs; listen; history; text; internal format)

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