a(n) is the number of times that sums 3 +- 5 +- 7 +- 11 +- ... +- prime(2n+1) of the first 2n odd primes is zero. There are 2^(2n-1) choices for the sign patterns.
A083309
a(n) is the number of times that sums 3 +- 5 +- 7 +- 11 +- ... +- prime(2n+1) of the first 2n odd primes is zero. There are 2^(2n-1) choices for the sign patterns.
Terms
- a(0) =0a(1) =0a(2) =1a(3) =2a(4) =7a(5) =19a(6) =63a(7) =197a(8) =645a(9) =2172a(10) =7423a(11) =25534a(12) =89218a(13) =317284a(14) =1130526a(15) =4033648a(16) =14515742a(17) =52625952a(18) =191790090a(19) =702333340a(20) =2585539586a(21) =9570549372a(22) =35562602950a(23) =131774529663a(24) =491713178890
External references
- oeis: A083309