A074936 Number of perfect powers between two successive nonprime prime powers.

0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 3, 0, 0, 1, 0, 3, 0, 1, 1, 1, 1, 1, 4, 0, 3, 2, 2, 1, 0, 0, 1, 4, 2, 4, 1, 2, 2, 3, 0, 1, 6, 1, 1, 0, 6, 2, 7, 3, 1, 4, 1, 1, 2, 8, 3, 1, 0, 1, 1, 6, 1, 1, 9, 1, 5, 0, 5, 4, 1, 3, 0, 5, 1, 0, 10, 1, 3, 2, 12, 11, 2, 1, 1, 3

Offset

1,15

Links

Table of n, a(n) for n=1..88.

Eric Weisstein's World of Mathematics, Perfect Power.

Eric Weisstein's World of Mathematics, Prime Power.

Example

There are three perfect powers with composite roots between A025475(15)=169=13^2 and A025475(15+1)=243=3^5: 196=(2*7)^2, 216=3^5 and 225=(3*5)^2; therefore a(15)=3.
a(16)=0, since there are no perfect powers between A025475(16)=243=3^5 and A025475(16+1)=256=2^8.

Crossrefs

Cf. A001597, A025475.

Sequence in context: A331509 A171913 A342154 * A035655 A353323 A239446

Adjacent sequences: A074933 A074934 A074935 * A074937 A074938 A074939

Keyword

nonn

Author

Reinhard Zumkeller, Oct 10 2002

Status

approved