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a(n) is the least prime of the form (3^j*5^k - 1)/2, j > 0, k > 0, j + k = n. a(n) = 0 if no such prime exists.
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%I #8 Aug 28 2020 11:04:18

%S 7,37,67,337,607,3037,15187,27337,49207,683437,0,131835937,659179687,

%T 19929037,35872267,228881835937,2491129687,0,0,311391210937,

%U 12013549804687,0,235357947067,1176789735337,0,10591107618037,52955538090187,5675104819335937,608185958862304687

%N a(n) is the least prime of the form (3^j*5^k - 1)/2, j > 0, k > 0, j + k = n. a(n) = 0 if no such prime exists.

%Y Cf. A093625, A076481, A337424, A337425, A337426.

%K nonn

%O 2,1

%A _Hugo Pfoertner_, Aug 27 2020