Number of solutions to 5 +- 11 +- 17 +- 23 +- ... +- prime(4*n+1) = 0.

Terms

a(0) =0a(1) =1a(2) =1a(3) =2a(4) =2a(5) =5a(6) =28a(7) =102a(8) =242a(9) =835a(10) =3381a(11) =10115a(12) =39415a(13) =138555a(14) =465778a(15) =1741167a(16) =6081563a(17) =22156403a(18) =81090107a(19) =301185788a(20) =1098440558a(21) =4071519963a(22) =15235221189a(23) =56764430821a(24) =211797564907a(25) =790029575790