A143671 Number of terms in A144688 of length n.

10, 45, 150, 375, 750, 1200, 1713, 2227, 2492, 2492, 2225, 2041, 1575, 1132, 770, 571, 335, 180, 90, 44, 18, 12, 6, 3, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

Offset

1,1

Comments

Since any 5-digit member of A144688 must end in 0 or 5, a(5) = 2*a(4).

Similarly a(n) <= 2*a(n-1) for n = 6, 7, 8, 9, a(10) = a(9), and a(n) <= a(n-1) for n >= 11.

a(n) = 0 for n > 25.

Links

Table of n, a(n) for n=1..75.

Crossrefs

Cf. A144688.

Sequence in context: A027800 A005714 A175705 * A221532 A241432 A317020

Adjacent sequences: A143668 A143669 A143670 * A143672 A143673 A143674

Keyword

nonn,base

Author

Zak Seidov and N. J. A. Sloane, Feb 08 2009

Status

approved