A376023 a(1) = 1, for n >= 2, a(n) = abs(a(n - 1) + A376022(n)).

1, 0, 3, 10, 17, 19, 19, 18, 15, 9, 6, 65, 74, 78, 80, 80, 79, 76, 71, 63, 49, 9, 62, 77, 85, 90, 93, 94, 93, 90, 85, 78, 68, 52, 21, 204, 247, 266, 277, 284, 288, 290, 290, 289, 286, 281, 274, 264, 250, 229, 192, 62, 150, 182, 201, 214, 223, 229, 233, 235, 235, 234, 231

Offset

1,3

Links

John Tyler Rascoe, Table of n, a(n) for n = 1..10000

Example

a(1) = 1.
a(2) = abs(a(1) + A376022(2)) = abs(1+(-1)) = 0.
a(3) = abs(0 + A376022(3)) = abs(0 + (-3)) = 3.
a(4) = abs(3 + A376022(4)) = abs(3 + (-13)) = 10.
and so on.

Mathematica

s[1] = 1; s[n_] := s[n] = -1 + Floor[n*s[n-1]/(n + s[n-1])]; a[1] = 1; a[n_] := a[n] = Abs[a[n-1] + s[n]]; Array[a, 100] (* Amiram Eldar, Sep 06 2024 *)

Prog

(Python)
from itertools import count, islice
def a_gen():
    a, c = 1, 1
    for n in count(2):
        yield c
        b = -1+(n*a)//(n+a)
        d = abs(c + b)
        a = b
        c = d
A376023_list = list(islice(a_gen(), 100)) # John Tyler Rascoe, Sep 17 2024
(PARI) lista(nn)= my(a=-2, b=0); vector(nn, n, a=floor(n*a/(n+a))-1; b=abs(a+b)); \\ Ruud H.G. van Tol, Nov 28 2024

Crossrefs

Cf. A376022.

Sequence in context: A059911 A160375 A300017 * A176760 A188396 A356090

Adjacent sequences: A376020 A376021 A376022 * A376024 A376025 A376026

Keyword

nonn,look

Author

Ctibor O. Zizka, Sep 06 2024

Status

approved