login
Number of base-3 pyramids of height n.
1

%I #4 Mar 30 2012 16:52:01

%S 2,2,2,6,10,14,30,47,62,91,134,217,316,483,743,1118,1598,2422,3616,

%T 5316,8061,12284,18675,26946,39146,59339,90790,137602,206390,316184

%N Number of base-3 pyramids of height n.

%C See Caldwell and Rupinski for precise definition.

%D C. K. Caldwell and A. Rupinski, Pyramids of 3-powerful primes, Mathematical Spectrum, 43 (No. 2, 2010/2011), 65-69.

%Y Cf. A186506.

%K base,nonn

%O 1,1

%A _N. J. A. Sloane_, Feb 22 2011