Number of subsets of {1,2,3,...,n} that sum to 0 mod 11.

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =3a(6) =6a(7) =12a(8) =24a(9) =47a(10) =94a(11) =188a(12) =374a(13) =746a(14) =1490a(15) =2978a(16) =5958a(17) =11916a(18) =23832a(19) =47664a(20) =95326a(21) =190652a(22) =381304a(23) =762604a(24) =1525204a(25) =3050404a(26) =6100804a(27) =12201612a(28) =24403224a(29) =48806448