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A329542 a(n) is the first occurrence of a composite number whose factorization without exponents contains exactly n circular loops (i.e., loops in digits 0, 6, 8, 9) on each side of the equals sign.

%I A329542 #16 Dec 02 2019 14:32:21
%S A329542 76,166,801,8067,38804,88181,586668,3680818,6899086,40888802,
%T A329542 168888169,868862887,884888909,4088888618,6898889086,40888888618,
%U A329542 108088888891,864888888892,1928888888668,16888888880873,8848888888909,40888888888802,120888888888896,968888888886830
%N A329542 a(n) is the first occurrence of a composite number whose factorization without exponents contains exactly n circular loops (i.e., loops in digits 0, 6, 8, 9) on each side of the equals sign.
%H A329542 Chris K. Caldwell and G. L. Honaker, Jr., <a href="https://primes.utm.edu/curios/page.php?curio_id=36881">Prime Curios! 76</a>
%e A329542 a(1) = 76 because 76 = 2*2*19, and there is exactly one loop on each side of the equals sign.
%e A329542 a(2) = 166 because 166 = 2*83, and there are exactly two loops on each side of the equals sign, etc. Note that '8' contains two loops.
%t A329542 cntLo[n_] := Plus @@ ({1,0,0,0,0,0,1,0,2,1}[[IntegerDigits[n] + 1]]);  cntF[n_] := Plus @@ (cntLo /@ First /@ FactorInteger[n]); a[n_] := Block[{k=1}, While[ cntLo[k] != n || cntF[k] != n || PrimeQ[k], k++]; k]; Array[a, 8] (* _Giovanni Resta_, Nov 18 2019 *)
%Y A329542 Cf. A000040, A001743.
%K A329542 nonn,base
%O A329542 1,1
%A A329542 _G. L. Honaker, Jr._, Nov 16 2019
%E A329542 a(5)-a(10) from Chuck Gaydos
%E A329542 a(11)-a(24) from _Giovanni Resta_, Nov 18 2019