A197917 Suppose n has prime factorization n=p1^a1*p2^a2*...*pk^ak and that D(n) is A006218, then n has all D(ai) even.

1, 16, 32, 64, 81, 128, 243, 256, 625, 729, 1296, 2187, 2401, 2592, 3125, 3888, 5184, 6561, 7776, 10000, 10368, 11664, 14641, 15552, 15625, 16807, 20000, 20736, 23328, 28561, 31104, 34992, 38416, 40000, 46656, 50000, 50625, 62208, 65536, 69984, 76832, 78125

Offset

1,2

Comments

Equivalently, for all exponents e in the factorization of n, floor(sqrt(e)) is even. [Charles R Greathouse IV, Oct 20 2011]

Links

Table of n, a(n) for n=1..42.

StackExchange, Question 73354

Prog

(PARI) is(n)=my(f=factor(n)[, 2]); for(i=1, #f, if(sqrtint(f[i])%2, return(0))); 1 \\ Charles R Greathouse IV, Oct 20 2011

Crossrefs

Cf. A006218.

Sequence in context: A036967 A076468 A246550 * A317475 A335161 A239751

Adjacent sequences: A197914 A197915 A197916 * A197918 A197919 A197920

Keyword

nonn

Author

A. Neves, Oct 19 2011

Status

approved