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A108632 Semiprimes with prime digits (only digits 2,3,5,7 in semiprimes). 4
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Complement of 108631 in the class of semiprimes.

LINKS

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

MATHEMATICA

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 *)

CROSSREFS

Cf. A108631.

Sequence in context: A070809 A280646 A178423 * A045096 A227408 A234540

Adjacent sequences:  A108629 A108630 A108631 * A108633 A108634 A108635

KEYWORD

nonn,base

AUTHOR

Zak Seidov, Jun 13 2005

STATUS

approved

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Last modified May 23 06:21 EDT 2017. Contains 286909 sequences.