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A046395
Palindromes that are the product of 5 distinct primes.
4
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
See A373465 for the similar sequence where only distinct prime divisors are counted, but may occur to higher powers. - M. F. Hasler, Jun 06 2024
LINKS
FORMULA
Intersection of A002113 and A046387.
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. A002113 (palindromes), A051270 (omega(.) = 5).
Cf. A046331 (palindromes with 5 prime factors counted with multiplicity), A373465 (counting only distinct prime divisors).
Sequence in context: A343432 A115429 A373465 * A143043 A031605 A239176
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
Name edited to avoid confusion by M. F. Hasler, Jun 06 2024
STATUS
approved