A081323 a(n) = L(P(n)), where L = Lucas numbers A000032, P = Pell numbers A000129.

2, 1, 3, 11, 322, 1149851, 425730551631123, 208406472252232726621841472637412401, 18490864749804416780204061487408593066264011288598603441079481989361240762271783793922

Offset

0,1

Links

Table of n, a(n) for n=0..8.

Formula

a:= n-> (<<1|1>, <1|0>>^((<<2|1>, <1|0>>^n)[1, 2]). <<2, -1>>)[1, 1]:

seq(a(n), n=0..8); # Alois P. Heinz, Sep 19 2019

Mathematica

l[n_] := l[n] = l[n - 1] + l[n - 2]; l[0] = 2; l[1] = 1; p[n_] := p[n] = 2p[n - 1] + p[n - 2]; p[0] = 0; p[1] = 1; Table[l[p[n]], {n, 0, 8}]
LucasL[LinearRecurrence[{2, 1}, {0, 1}, 10]] (* Harvey P. Dale, Sep 19 2019 *)

Crossrefs

Cf. A000032, A000129, A081322.

Sequence in context: A369242 A187111 A122050 * A173958 A175243 A168217

Adjacent sequences: A081320 A081321 A081322 * A081324 A081325 A081326

Keyword

easy,nonn

Author

Mario Catalani (mario.catalani(AT)unito.it), Mar 18 2003

Extensions

Typo in a(8) corrected by Harvey P. Dale, Sep 19 2019

Status

approved