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%I #7 Jan 27 2019 21:26:39
%S 1,2,1,33,3,1,19940,3,2,1,204323,213,155,3,1,380480345,213,7572,3,2,1
%N Square array read by antidiagonals: a(n, d) is the smallest number that begins an arithmetic progression with common difference d of n numbers with the same prime signature.
%C First two columns are A034173 and A113457. First three rows are A000012, A086489 and A113458.
%e a(3, 2) = 3 because 3, 5 and 7 have the same prime signature.
%K nonn,tabl,less
%O 1,2
%A _David Wasserman_, Jan 08 2006; corrected Jan 08 2006