A080095 Let sum(k>=0, k^n/(2*k+1)!) = (x(n)*e + y(n)/e)/z(n), where x(n) and z(n) are >0, then a(n)=z(n).

2, 8, 16, 16, 64, 128, 128, 512, 1024, 1024, 4096, 8192, 8192, 32768, 65536, 65536, 262144, 524288, 524288, 2097152, 4194304, 4194304, 16777216, 33554432, 33554432, 134217728, 268435456, 268435456, 1073741824, 2147483648

Offset

1,1

Links

Table of n, a(n) for n=1..30.

Index to divisibility sequences

Formula

a(n) = 2^b(n) and {b(n)}={1, 3, 4, 4, 6, 7, 7, 9, 10, 10, 12, 13, 13, 15, ..} where b(3n-2)=3n-2, b(3n-1)=3n, b(3n)=b(3n+1)=3n+1, for n>0.

Prog

(PARI) apply(n->2^n, Vec((1+2*x+x^2-x^3)/(1-x-x^3+x^4)+O(x^30))) \\ Charles R Greathouse IV, Apr 09 2012

Crossrefs

Cf. A080093, A080094.

Sequence in context: A182039 A359228 A174882 * A193219 A213249 A155853

Adjacent sequences: A080092 A080093 A080094 * A080096 A080097 A080098

Keyword

nonn,easy

Author

Benoit Cloitre and Paul D. Hanna, Jan 28 2003

Status

approved