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A064907 Semiprimes p1*p2 such that p2 mod p1 = 9, with p2 > p1.

%I A064907 #19 Jul 31 2023 20:38:34
%S A064907 341,583,731,793,893,1067,1469,1793,1807,1943,2201,2323,2483,2519,
%T A064907 2761,3043,3071,3487,3497,3781,4213,4439,4511,4777,4841,4849,4939,
%U A064907 5497,5809,5933,5947,6511,6539,6989,7093,7117,7391,7493,7601,7613,7783,7891,7967
%N A064907 Semiprimes p1*p2 such that p2 mod p1 = 9, with p2 > p1.
%H A064907 John Cerkan, <a href="/A064907/b064907.txt">Table of n, a(n) for n = 1..10000</a>
%t A064907 spQ[n_]:=Module[{fi=FactorInteger[n][[All,1]]},PrimeOmega[n]==2&&Mod[ fi[[2]],fi[[1]]]==9]; Select[Range[8000],spQ]//Quiet (* _Harvey P. Dale_, Aug 02 2019 *)
%o A064907 (Python)
%o A064907 from sympy import factorint
%o A064907 def is_A064907(n):
%o A064907     f = factorint(n)
%o A064907     return (sum([f[i] for i in f]) == 2) and (max(f) % min(f) == 9)
%o A064907 def list_A064907(cnt):
%o A064907     inx = 0
%o A064907     n = 1
%o A064907     an = []
%o A064907     while inx < cnt:
%o A064907         if is_A064907(n):
%o A064907             an.append(n)
%o A064907             inx += 1
%o A064907         n += 2
%o A064907     return an #_John Cerkan_, Apr 14 2018
%o A064907 (PARI) isok(n) = my(f = factor(n)); (#f~ == 2) && (vecmax(f[,2]) < 2) && ((f[2,1] % f[1,1]) == 9); \\ _Michel Marcus_, Apr 16 2018
%Y A064907 Cf. A001358 (p2 mod p1 = 0), A064899-A064911.
%K A064907 nonn
%O A064907 1,1
%A A064907 _Patrick De Geest_, Oct 13 2001
%E A064907 Offset changed by _John Cerkan_, Apr 12 2018