((p-1)/2)! mod p for odd primes p.

Terms

a(0) =1a(1) =2a(2) =6a(3) =10a(4) =5a(5) =13a(6) =18a(7) =1a(8) =12a(9) =1a(10) =31a(11) =9a(12) =42a(13) =46a(14) =23a(15) =1a(16) =11a(17) =66a(18) =1a(19) =27a(20) =78a(21) =1a(22) =34a(23) =22a(24) =91a(25) =102a(26) =1a(27) =33a(28) =15a(29) =126