OFFSET
0,1
COMMENTS
Number of words less than or equal to the concatenation of the n-th row of Pascal's Triangle.
a(n) = 2 * A055612(n). - Reinhard Zumkeller, Jan 31 2015
Same as A129824. - Georg Fischer, Oct 14 2018
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 0..69
FORMULA
a(n) = Product_{k=0..n} (binomial(n,k) + 1).
EXAMPLE
Row 2 is 1 2 1 and we have 000, 001, 010, 011, 020, 021, 100, 101, 110, 111, 120 and 121 so a(2)=12.
MATHEMATICA
Table[Product[Binomial[n, k] + 1, {k, 0, n}], {n, 0, 15}] (* T. D. Noe, Mar 21 2013 *)
CROSSREFS
KEYWORD
dead
AUTHOR
Jon Perry, Mar 21 2013
STATUS
approved