A356551 a(n) = A005132(n+2) - A005132(n).

3, 5, -1, 1, 11, 13, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, 35, 37, -1, 1, -1, -45, 1, -1, 1, -1, 1, -1, 1, -1, 1, 65, 67, -1, 1, -1, -75, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, 131, 133, -1, 1, -1

Offset: 0

Author

Paul Curtz, Aug 12 2022

Keywords

• sign

Links

• Index entries for sequences related to Recamán's sequence

Crossrefs

Cf. A005132, A160356.

Programs

PARI

vR(nn) = my(s, t, v=vector(nn)); for(n=1, nn, s=bitor(s, 1<A005132
lista(nn) = my(v=vR(nn+1)); vector(nn, k, v[k+2] - v[k]); \\ Michel Marcus, Aug 14 2022

Python

from itertools import count, islice
def A356551_gen(): # generator of terms
    b, c, aset = 0, 1, {0}
    for n in count(2):
        aset.add(c)
        a, b, c = b, c, d if (d:=c-n)>=0 and d not in aset else c+n
        yield c-a
A356551_list = list(islice(A356551_gen(),70)) # Chai Wah Wu, Sep 15 2022