cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A046369 Numbers with exactly 3 prime factors (counted with multiplicity), all of which are palindromes.

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%I A046369 #18 Jul 04 2025 18:09:53
%S A046369 8,12,18,20,27,28,30,42,44,45,50,63,66,70,75,98,99,105,110,125,147,
%T A046369 154,165,175,231,242,245,275,343,363,385,404,524,539,604,605,606,724,
%U A046369 764,786,847,906,909,1010,1086,1146,1179,1252,1310,1331,1359,1412,1414
%N A046369 Numbers with exactly 3 prime factors (counted with multiplicity), all of which are palindromes.
%H A046369 Andrew Howroyd, <a href="/A046369/b046369.txt">Table of n, a(n) for n = 1..1000</a>
%t A046369 Select[Range[1500],PrimeOmega[#]==3&&AllTrue[FactorInteger[#][[;;,1]],PalindromeQ]&] (* _Harvey P. Dale_, Jul 04 2025 *)
%o A046369 (Python)
%o A046369 from sympy import factorint
%o A046369 def pal(n): s = str(n); return s == s[::-1]
%o A046369 def ok(n):
%o A046369     f = factorint(n)
%o A046369     return sum(f.values())==3 and all(pal(p) for p in f)
%o A046369 print([k for k in range(1415) if ok(k)]) # _Michael S. Branicky_, Jul 04 2025
%Y A046369 Intersection of A033620 and A014612.
%Y A046369 Cf. A046401.
%K A046369 nonn,base
%O A046369 1,1
%A A046369 _Patrick De Geest_, Jun 15 1998
%E A046369 Offset changed by _Andrew Howroyd_, Aug 14 2024
%E A046369 Name clarified by _Sean A. Irvine_, Jul 04 2025