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A064909 Semiprimes p1*p2 such that p2 > p1 and p2 mod p1 = 11.

%I A064909 #26 May 15 2021 11:47:07
%S A064909 481,1157,1343,1921,2171,2263,2369,2509,3077,3097,3427,3523,3683,4171,
%T A064909 4537,4541,4811,5213,5263,5389,5543,6107,6227,6707,7123,7241,8279,
%U A064909 8593,8621,8717,8857,8873,9353,9607,10411,10537,11359,11461,11567,11747,11761,11819
%N A064909 Semiprimes p1*p2 such that p2 > p1 and p2 mod p1 = 11.
%H A064909 John Cerkan, <a href="/A064909/b064909.txt">Table of n, a(n) for n = 1..10000</a>
%t A064909 pmp11Q[n_]:=Module[{fi=FactorInteger[n][[All,1]]},Mod[fi[[2]],fi[[1]]] == 11]; Select[ Range[12000],PrimeNu[#]==PrimeOmega[#]==2&&pmp11Q[#]&] (* _Harvey P. Dale_, Jun 25 2018 *)
%o A064909 (Python)
%o A064909 from sympy import factorint
%o A064909 def is_A064909(n):
%o A064909     f = factorint(n)
%o A064909     return (sum([f[i] for i in f]) == 2) and (max(f) % min(f) == 11)
%o A064909 def first_A064909(n):
%o A064909     x = 1
%o A064909     an = []
%o A064909     while len(an) < n:
%o A064909         if is_A064909(x): an.append(x)
%o A064909         x += 2
%o A064909     return an # _John Cerkan_, Apr 14 2018
%o A064909 (PARI) isok(n) = my(f = factor(n)); (#f~ == 2) && (vecmax(f[,2]) < 2) && ((f[2,1] % f[1,1]) == 11);
%Y A064909 Cf. A001358 (p2 mod p1 = 0), A064899-A064911.
%K A064909 nonn
%O A064909 1,1
%A A064909 _Patrick De Geest_, Oct 13 2001
%E A064909 Offset and name fixed by _John Cerkan_, Apr 12 2018