a(1) = 1; a(2n) is the smallest prime == 1 mod (a(2n-1)) and a(2n+1) is the smallest composite number == 1 (mod a(2n)).
A075340
a(1) = 1; a(2n) is the smallest prime == 1 mod (a(2n-1)) and a(2n+1) is the smallest composite number == 1 (mod a(2n)).
Terms
- a(0) =1a(1) =2a(2) =9a(3) =19a(4) =20a(5) =41a(6) =42a(7) =43a(8) =44a(9) =89a(10) =90a(11) =181a(12) =182a(13) =547a(14) =548a(15) =1097a(16) =1098a(17) =7687a(18) =7688a(19) =15377a(20) =15378a(21) =30757a(22) =30758a(23) =276823a(24) =276824a(25) =553649a(26) =553650a(27) =2768251a(28) =2768252a(29) =8304757
External references
- oeis: A075340