Number of subsets of {1,2,3,...,n} that sum to 0 mod 13.

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =2a(6) =5a(7) =10a(8) =20a(9) =39a(10) =79a(11) =158a(12) =316a(13) =632a(14) =1262a(15) =2522a(16) =5042a(17) =10082a(18) =20164a(19) =40330a(20) =80660a(21) =161320a(22) =322638a(23) =645278a(24) =1290556a(25) =2581112a(26) =5162224a(27) =10324444a(28) =20648884a(29) =41297764