A111415 a(n) = f(f(n+1)) - f(f(n)), where f(m) = Pell(m) = A000129(m).

1, 1, 27, 13831, 44560468289, 220167382952941205430116129, 17280083176824678419775054525017769508688140582155308813842797363

Offset

0,3

Links

Alois P. Heinz, Table of n, a(n) for n = 0..9

Maple

b:= n-> (<<2|1>, <1|0>>^n)[1, 2]:
a:= n-> b(b(n+1))-b(b(n)):
seq(a(n), n=0..6);  # Alois P. Heinz, Feb 10 2026

Mathematica

Differences[Nest[Fibonacci[#, 2] &, Range[0, 8], 2]] (* Paolo Xausa, Feb 18 2026 *)

Crossrefs

Cf. A000129.

First differences of A393297.

Sequence in context: A001321 A385211 A263601 * A036534 A167731 A357506

Adjacent sequences: A111412 A111413 A111414 * A111416 A111417 A111418

Keyword

nonn

Author

N. J. A. Sloane, Nov 12 2005

Extensions

Definition corrected by N. J. A. Sloane, Feb 14 2018

Status

approved