A105117 Minimal number of perfect powers needed to sum to prime(n).

2, 3, 2, 4, 3, 2, 2, 3, 4, 2, 2, 2, 2, 2, 3, 2, 2, 2, 3, 3, 2, 3, 3, 2, 2, 2, 3, 3, 2, 2, 2, 3, 2, 3, 2, 3, 2, 3, 4, 2, 3, 2, 3, 2, 2, 3, 3, 2, 3, 2, 2, 3, 2, 2, 2, 3, 2, 3, 2, 2, 2, 2, 2, 3, 2, 2, 3, 2, 2, 2, 2, 2, 3, 2, 2, 3, 2, 2, 2, 2, 3, 2, 3, 2, 2, 2, 2, 2, 2, 3, 3, 3, 2, 3, 2, 3, 2, 2, 3, 2, 3, 2, 3, 2, 3

Offset

1,1

Links

Table of n, a(n) for n=1..105.

Eric Weisstein's World of Mathematics, Perfect Power.

Example

a(4) = 4 since prime(4) = 7 = 1+1+1+4.
a(8) = 3 since prime(8) = 19 = 1+9+9.
a(11) = 2 since prime(11) = 31 = 4+27.
a(14) = 2 since prime(14) = 43 = 16+27.

Crossrefs

Cf. A001597.

Sequence in context: A277859 A308566 A288535 * A100876 A089215 A238766

Adjacent sequences: A105114 A105115 A105116 * A105118 A105119 A105120

Keyword

easy,nonn

Author

Giovanni Teofilatto, Apr 08 2005

Extensions

Corrected and extended by Ray Chandler, May 05 2005

Status

approved