A164675 a(n) = 8*a(n-2) for n > 2; a(1) = 1, a(2) = 12.

1, 12, 8, 96, 64, 768, 512, 6144, 4096, 49152, 32768, 393216, 262144, 3145728, 2097152, 25165824, 16777216, 201326592, 134217728, 1610612736, 1073741824, 12884901888, 8589934592, 103079215104, 68719476736, 824633720832

Offset: 1

Author

Klaus Brockhaus, Aug 20 2009

Keywords

• nonn
• easy

Comments

Interleaving of A001018 and 12*A001018.

Binomial transform is A164539.

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..500
• Index entries for linear recurrences with constant coefficients, signature (0,8).

Crossrefs

Cf. A001018 (powers of 8), A164539.

Programs

Magma

[ n le 2 select 11*n-10 else 8*Self(n-2): n in [1..26] ];

Mathematica

Riffle[#, 12*#] & [8^Range[0, 14]] (* or *)
LinearRecurrence[{0, 8}, {1, 12}, 30] (* Paolo Xausa, Apr 22 2024 *)

Formula

a(n) = (5+(-1)^n)*2^(1/4*(6*n-11+3*(-1)^n)).

G.f.: x*(1+12*x)/(1-8*x^2).