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%I #20 Nov 15 2023 01:14:04
%S 4,6,9,34,123,789,901,1234,34567,56789,901234,1234567,7890123,
%T 567890123,12345678901,345678901234567,4567890123456789,
%U 12345678901234567,890123456789012345,3456789012345678901,456789012345678901234,123456789012345678901234567,1234567890123456789012345678901,23456789012345678901234567890123
%N Semiprimes with consecutive (ascending) digits.
%C This is to semiprimes A001358 as A006055 is to primes.
%e a(9) = 34567 because it is semiprime 13 * 2659, and (3,4,5,6,7) are consecutive ascending digits.
%p R:= 4, 6, 9: V:= [$1..9]:
%p for d from 2 to 50 do
%p V:= map(n -> 10*n + ((n+1) mod 10), V);
%p W:= select(t -> numtheory:-bigomega(t)=2, V);
%p R:= R, op(W);
%p od:
%p R; # _Robert Israel_, Nov 15 2023
%Y Cf. A001358, A118697, A059043, A006055, A161760.
%K nonn,base
%O 1,1
%A _Jonathan Vos Post_, Aug 12 2012
%E Corrected and extended by _R. J. Mathar_, Aug 13 2012
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