A359502 a(n) = a(n-2)^2 + a(n-1) + 1 for n >= 2 with a(0) = 0 and a(1) = 1.

0, 1, 2, 4, 9, 26, 108, 785, 12450, 628676, 155631177, 395389144154, 24221458643549484, 156332599536291235925201, 586679058977510608947573592591458, 24439881677774993432884951095586547256059481860

Offset

0,3

Links

Table of n, a(n) for n=0..15.

Mathematica

a[0] = 0; a[1] = 1; a[n_] := a[n] = a[n - 2]^2 + a[n - 1] + 1; Array[a, 16, 0] (* Amiram Eldar, Jan 05 2023 *)

Prog

(Python)
# a generator
def agen_q():
    a, b = 0, 1
    while 1:
        yield a
        a, b = b, (a * a) + b + 1
f = agen_q(); print([next(f) for _ in range(20)])

Crossrefs

Cf. A000278, A000283.

Sequence in context: A114957 A002773 A112706 * A110138 A148085 A003320

Adjacent sequences: A359499 A359500 A359501 * A359503 A359504 A359505

Keyword

nonn

Author

Andrew Wall, Jan 03 2023

Status

approved