A108631 -id:A108631 - cp's OEIS frontend

A108632 Semiprimes with prime digits (only digits 2,3,5,7 in semiprimes).

22, 25, 33, 35, 55, 57, 77, 235, 237, 253, 323, 327, 335, 355, 377, 527, 533, 535, 537, 553, 573, 723, 737, 753, 755, 2227, 2253, 2257, 2323, 2327, 2335, 2353, 2533, 2537, 2573, 2577, 2722, 2723, 2733, 2735, 2757, 2773, 3223, 3227, 3233, 3235, 3273, 3277

Offset: 1

Zak Seidov, Jun 13 2005

Complement of 108631 in the class of semiprimes.

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Cf. A108631.

fQ[n_]:=Plus@@Last/@FactorInteger[n]==2&&Union[{2, 3, 5, 7}, IntegerDigits[n]]=={2, 3, 5, 7};Select[Range[4000], fQ[ # ]&]
Select[FromDigits/@Flatten[Table[Tuples[{2,3,5,7},n],{n,2,4}],1],PrimeOmega[#]==2&] (* Harvey P. Dale, Oct 19 2012 *)

A242739 Semiprimes having only straight digits.

Original entry on oeis.org

4, 14, 74, 77, 111, 141, 177, 411, 417, 447, 471, 717, 771, 1111, 1114, 1141, 1147, 1174, 1177, 1411, 1417, 1441, 1477, 1711, 1714, 1717, 1774, 4117, 4141, 4171, 4174, 4411, 4414, 4417, 4471, 4474, 4711, 4714, 4717, 4741, 4747, 4771, 4777, 7111, 7114, 7117, 7141

Offset: 1

K. D. Bajpai, May 21 2014

A straight digit semiprime has only the straight digits, i.e., 1, 4 or 7.

Intersection of A001358 and A028373. - Michel Marcus, May 25 2014

			471 = 3 * 157 is semiprime and has only straight digits 4, 7 and 1. Hence it is in the sequence.
1147 =  31 * 37 is semiprime and has only straight digits 1, 1, 4 and 7. Hence it is in the sequence.

K. D. Bajpai, Table of n, a(n) for n = 1..1727

Cf. A001358, A028373, A079651, A108631, A108632.

A242739 = {}; Do[a = PrimeOmega[n]; If [a == 2 && Intersection[IntegerDigits[n], {0, 2, 3, 5, 6, 8, 9}] == {}, AppendTo[A242739, n]], {n, 8000}]; A242739
Table[Select[FromDigits/@Tuples[{1,4,7},n],PrimeOmega[#]==2&],{n,4}]//Flatten (* Harvey P. Dale, Sep 23 2022 *)

cp's OEIS Frontend

A108632 Semiprimes with prime digits (only digits 2,3,5,7 in semiprimes).

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