a(n) is the smallest integer >= a(n-1) such that prime(n)*2^a(n)-1 is a prime number.

A258868

a(n) is the smallest integer >= a(n-1) such that prime(n)*2^a(n)-1 is a prime number.

Terms

    a(0) =1a(1) =1a(2) =2a(3) =5a(4) =26a(5) =287a(6) =356a(7) =395a(8) =544a(9) =11008a(10) =21957a(11) =32125a(12) =42450a(13) =50867a(14) =55408a(15) =206970a(16) =358276a(17) =384287a(18) =403461a(19) =735802a(20) =783831a(21) =969795a(22) =1192950a(23) =1383108

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