A263106 Semiprimes such that the leftward cyclic permutation of its decimal digits is also semiprime.

4, 6, 9, 15, 22, 26, 33, 39, 49, 51, 55, 58, 62, 77, 85, 93, 94, 111, 122, 129, 134, 141, 145, 155, 158, 159, 161, 177, 178, 183, 185, 187, 202, 206, 214, 226, 254, 262, 298, 303, 309, 314, 321, 339, 341, 355, 358, 362, 371, 381, 391, 393, 394, 403, 407, 413

Offset: 1

Author

Zak Seidov, Oct 09 2015

Keywords

• nonn
• base

Comments

First 18 terms are also in A085751.

Examples

			15 = 3 * 5, 51 = 3 * 17; 889 = 7 * 17, 898 = 2 * 449.
		

Links

• Zak Seidov, Table of n, a(n) for n = 1..65049 (all terms up to 10^6)

Crossrefs

Cf. A001292, A001358, A085751.

Programs

Mathematica

Select[Range[4, 1000], 2 == PrimeOmega[#] == PrimeOmega[FromDigits[RotateLeft[IntegerDigits[#]]]] &]

PARI

shl(n)=if(n<10,return(n)); my(d=digits(n)); fromdigits(concat(d[2..#d], d[1]))
is(n)=bigomega(n)==2 && bigomega(shl(n))==2 \\ Charles R Greathouse IV, Oct 12 2015