OFFSET
1,2
COMMENTS
1
23
101
1121
32021
222330...
MATHEMATICA
t = Flatten[IntegerDigits[Range[1500], 4]]; t[[Table[n(n + 1)/2, {n, 105}]]]
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Robert G. Wilson v, Mar 16 2005
STATUS
approved