Define polynomials Pn by P0 = 0, P1 = x, P2 = P1 + P0, P3 = P2 * P1, P4 = P3 + P2, etc. alternately adding or multiplying. For even n > 2k, then first k coefficients of Pn remain unchanged and their values are the first k terms of the sequence.
A045761
Define polynomials Pn by P0 = 0, P1 = x, P2 = P1 + P0, P3 = P2 * P1, P4 = P3 + P2, etc. alternately adding or multiplying. For even n > 2k, then first k coefficients of Pn remain unchanged and their values are the first k terms of the sequence.
Terms
- a(0) =0a(1) =1a(2) =1a(3) =1a(4) =2a(5) =3a(6) =6a(7) =12a(8) =24a(9) =50a(10) =107a(11) =232a(12) =508a(13) =1124a(14) =2513a(15) =5665a(16) =12858a(17) =29356a(18) =67371a(19) =155345a(20) =359733a(21) =836261a(22) =1950829a(23) =4565305a(24) =10714501a(25) =25212843a(26) =59474318a(27) =140609809a(28) =333126672a(29) =790764280
External references
- oeis: A045761