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A109989 4-almost primes (A014613) ordered alphabetically by where they occur in A000052. 1

%I #3 Mar 30 2012 18:40:29

%S 88,84,81,54,56,40,90

%N 4-almost primes (A014613) ordered alphabetically by where they occur in A000052.

%C A109986 is primes ordered alphabetically by where they occur in A000052. A109987 is semiprimes ordered alphabetically by where they occur in A000052. A109988 is 3-almost primes ordered alphabetically by where they occur in A000052.

%e a(1) = 88 because eighty-eight is the first 4-almost prime in alphabetical order, there being no 1-digit 4-almost primes.

%e a(2) = 84 because eighty-four is the second 2-digit 4-almost prime in alphabetical order.

%Y Cf. A000052, A014613, A109986, A109987, A109988.

%K base,easy,nonn,word

%O 1,1

%A _Jonathan Vos Post_, Jul 07 2005

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Last modified April 25 13:12 EDT 2024. Contains 371969 sequences. (Running on oeis4.)