A046395 Palindromes with exactly 5 distinct prime factors.

6006, 8778, 20202, 28182, 41514, 43134, 50505, 68586, 87978, 111111, 141141, 168861, 202202, 204402, 209902, 246642, 249942, 262262, 266662, 303303, 323323, 393393, 399993, 438834, 454454, 505505, 507705, 515515, 516615, 519915, 534435, 535535, 543345

Offset

1,1

Comments

No exponent of the distinct prime factors can be greater than one, i.e., no prime powers are permitted. - Harvey P. Dale, Apr 09 2021 at the suggestion of Sean A. Irvine

Links

Harvey P. Dale, Table of n, a(n) for n = 1..500

Example

505505 = 5 * 7 * 11 * 13 * 101.

Mathematica

Select[Range[550000], PalindromeQ[#]&&PrimeNu[#]==PrimeOmega[#]==5&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Apr 09 2021 *)

Crossrefs

Cf. A046331.

Sequence in context: A250514 A343432 A115429 * A143043 A031605 A239176

Adjacent sequences: A046392 A046393 A046394 * A046396 A046397 A046398

Keyword

nonn,base

Author

Patrick De Geest, Jun 15 1998

Extensions

Corrected at the suggestion of Sean A. Irvine by Harvey P. Dale, Apr 09 2021

Status

approved