A085086 a(1) = 1; if n is composite then a(n) = Sum_{i < n, i not prime} a(i), else if n is prime then a(n) = sum_{ j < n, j is a noncomposite} a(j).

1, 1, 2, 1, 4, 2, 8, 4, 8, 16, 16, 32, 32, 64, 128, 256, 64, 512, 128, 1024, 2048, 4096, 256, 8192, 16384, 32768, 65536, 131072, 512, 262144, 1024, 524288, 1048576, 2097152, 4194304, 8388608, 2048, 16777216, 33554432, 67108864, 4096, 134217728, 8192

Offset: 1

Author

Amarnath Murthy and Meenakshi Srikanth (menakan_s(AT)yahoo.com), Jul 02 2003

Keywords

• nonn

Examples

			a(7) = a(1) + a(2) + a(3) + a(5) = 8.
		

Crossrefs

Cf. A002033, A045545.

Formula

a(p(i)) = 2^(i-1); a(A002808(i)) = 2^(i-1). - David Wasserman, Jan 25 2005

Extensions

More terms from David Wasserman, Jan 25 2005