A180496 Largest palindromic prime < n-th-semiprime.

3, 5, 7, 7, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 101, 101, 101, 101, 101, 101, 101, 101, 101, 131, 131, 131, 131, 131, 131, 131, 151, 151, 151, 151, 151, 151, 151, 151, 181, 181, 181

Offset

1,1

Links

Table of n, a(n) for n=1..61.

Mathematica

With[{nn=150}, Module[{palpr=Reverse[Select[Prime[Range[nn]], IntegerDigits[ #] == Reverse[ IntegerDigits[#]]&]], semis = Select[Range[2nn], PrimeOmega[ #] == 2&]}, Flatten[Table[Select[palpr, #<semis[[n]]&, 1], {n, Length[ semis]}]]]] (* Harvey P. Dale, Jun 12 2014 *)

Crossrefs

Sequence in context: A254764 A109535 A361327 * A082433 A082683 A084752

Adjacent sequences: A180493 A180494 A180495 * A180497 A180498 A180499

Keyword

base,easy,nonn

Author

Giovanni Teofilatto, Sep 08 2010

Status

approved