%I A053427
%S A053427 4,5,6,8,9,18,25,66,87,134,145,200,384,443,502,589,625,638,1082,1235,
%T A053427 1236,1439,1892,2014,2355,2380,2592,2676,2981,3406,3908,4775,5885
%N A053427 Catalan[n]-1 is prime.
%C A053427 Primality up to Catalan[5885]-1 proved by PrimeForm.
%e A053427 Catalan[25]-1=50!/25!/26!-1=4861946401451 is prime.
%Y A053427 Cf. A000108, A053429.
%Y A053427 Sequence in context: A030751 A152870 A087947 this_sequence A037354 A035065 
               A035067
%Y A053427 Adjacent sequences: A053424 A053425 A053426 this_sequence A053428 A053429 
               A053430
%K A053427 nonn
%O A053427 1,1
%A A053427 David Broadhurst (D.Broadhurst(AT)open.ac.uk), Jan 10 2000