

A068623


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


4



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

1,1


LINKS

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


FORMULA

For n>=5, a(n) = 18*10^(2*n6) + 45*10^(n3) + 28 [From Max Alekseyev, Apr 25 2009]


CROSSREFS

Cf. A068618, A068619, A068621, A068622, A068624.
Sequence in context: A244613 A228281 A146977 * 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



