A324207 Numbers with exactly seven distinct exponents in their prime factorization, or seven distinct parts in their prime signature.

2677277333530800000, 2992251137475600000, 3164055030536400000, 3501054974617200000, 3536296798834800000, 3622198745365200000, 3748188266943120000, 4015916000296200000, 4189151592465840000, 4207150095548400000, 4280780335431600000, 4373290124002800000, 4429677042750960000

Offset

1,1

Links

David A. Corneth, Table of n, a(n) for n = 1..10000

Example

2677277333530800000 = 2^7 * 3^6 * 5^5 * 7^4 * 11^3 * 13^2 * 17 is in the sequence. There are exactly 7 distinct exponents; 1 through 7 in it.

Prog

(PARI) is(n) = #Set(factor(n)[, 2]) == 7

Crossrefs

Cf. A001221, A001222, A006939, A051270, A059404, A071625, A118914, A181819, A182855, A323014, A323022, A323024, A323025, A323056.

Sequence in context: A246234 A274814 A323534 * A288289 A104839 A219346

Adjacent sequences: A324204 A324205 A324206 * A324208 A324209 A324210

Keyword

nonn,easy

Author

David A. Corneth, Feb 17 2019

Status

approved