A046410 -id:A046410 - cp's OEIS frontend

A046330 Palindromes with exactly 4 prime factors (counted with multiplicity).

88, 232, 414, 424, 444, 484, 525, 585, 636, 666, 676, 686, 808, 858, 868, 999, 1881, 2002, 2332, 2442, 2662, 3003, 3663, 3773, 3993, 4114, 4444, 4774, 5005, 5115, 5225, 6116, 6556, 6666, 7007, 7227, 8668, 9999, 10101, 10701, 11011, 12321, 13431

Offset: 1

Patrick De Geest, Jun 15 1998

John Cerkan, Table of n, a(n) for n = 1..10000

Cf. A014613, A046317, A046410.

Select[Range[14000],PalindromeQ[#]&&PrimeOmega[#]==4&] (* Harvey P. Dale, Jul 07 2024 *)

A046394 Palindromes with exactly 4 distinct prime factors.

Original entry on oeis.org

858, 2002, 2442, 3003, 4774, 5005, 5115, 6666, 10101, 15351, 17871, 22422, 22722, 24242, 26562, 26962, 28482, 35853, 36363, 41314, 43734, 43834, 45654, 47874, 49494, 49794, 49894, 51015, 51315, 51415, 53535, 53835, 53935, 56865, 58485

Offset: 1

Patrick De Geest, Jun 15 1998

Robert Israel, Table of n, a(n) for n = 1..10000

Cf. A046330, A046410.

filter:= proc(n) local F;
  F:= ifactors(n)[2];
  nops(F)=4 and max(map(t->t[2],F))=1
end proc:
makepali:= proc(n,d) local L;
  L:= convert(n,base,10);
  if d::even then 10^(d/2)*n + add(L[i]*10^(d/2-i),i=1..d/2)
  else 10^((d-1)/2)*n + add(L[i]*10^((d+1)/2-i),i=2..(d+1)/2)
  fi
end proc:
select(filter, [seq(seq(makepali(x,d),
   x=10^ceil(d/2-1)..10^ceil(d/2)-1),d=1..6)]); # Robert Israel, Jun 05 2018

Select[Range[60000],PalindromeQ[#]&&PrimeNu[#]==Total[FactorInteger[#][[All,2]]] == 4&] (* Harvey P. Dale, Apr 07 2022 *)

A046378 Palindromes with exactly 4 palindromic prime factors (counted with multiplicity).

Original entry on oeis.org

88, 484, 525, 686, 808, 2662, 3773, 3993, 4444, 6666, 9999, 14641, 24442, 34643, 36663, 40804, 52525, 134431, 224422, 336633, 1234321, 1596951, 2060602, 3090903, 11333311, 14699641, 22888822, 66888866, 104060401, 125888521, 134969431, 367888763, 413979314

Offset: 1

Patrick De Geest, Jun 15 1998

			The palindrome 1596951 is a term since it has 4 factors 3^2 191 929, all palindromic.

Lars Blomberg, Table of n, a(n) for n = 1..320, terms < 10^16.

Cf. A046330, A046410.

More terms from Lars Blomberg, Nov 06 2015

cp's OEIS Frontend

A046330 Palindromes with exactly 4 prime factors (counted with multiplicity).

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A046394 Palindromes with exactly 4 distinct prime factors.

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A046378 Palindromes with exactly 4 palindromic prime factors (counted with multiplicity).

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