A322449 Numbers whose prime factorization contains only composite exponents.

1, 16, 64, 81, 256, 512, 625, 729, 1024, 1296, 2401, 4096, 5184, 6561, 10000, 11664, 14641, 15625, 16384, 19683, 20736, 28561, 32768, 38416, 40000, 41472, 46656, 50625, 59049, 65536, 82944, 83521, 104976, 117649, 130321, 153664, 160000, 186624, 194481, 234256

Offset

1,2

Comments

Differs from A117453 first at n = 13: a(13) = 5184 = 2^6 * 3^4, A117453(13) = 6561 = 3^8.

Links

Alois P. Heinz, Table of n, a(n) for n = 1..10000

Formula

Sum_{n>=1} 1/a(n) = Product_{p prime} (1 + Sum_{k in A002808} 1/p^k) = 1.1028952548... . - Amiram Eldar, Jul 02 2022

Example

5184 = 2^6 * 3^4 is a term because all exponents are composite numbers.

Crossrefs

Cf. A002808, A117453, A322448.

Sequence in context: A062320 A233330 A370787 * A117453 A340588 A352475

Adjacent sequences: A322446 A322447 A322448 * A322450 A322451 A322452

Keyword

nonn

Author

Alois P. Heinz, Dec 08 2018

Status

approved