A366913 a(n) is the least k such that A366912(k) = n.

1, 2, 3, 4, 9, 10, 23, 28, 29, 84, 170, 353, 805, 850, 2171, 4860, 11815, 28025, 31539, 131252, 318231, 406904, 1612758, 2461032, 9917597, 11551434, 36824781, 80492173, 206009383, 505512671, 1361256869, 2467754261

Offset

0,2

Comments

a(n) corresponds to the index of the first term of A364054 with height n.

Links

Table of n, a(n) for n=0..31.

Rémy Sigrist, PARI program

Rémy Sigrist, C++ program

Prog

(PARI) See Links section.
(C++) See Links section.
(Python)
from itertools import count
from sympy import nextprime
def A366913(n):
    a, aset, p, c = 1, {0, 1}, 2, 0
    for i in count(1):
        if c == n:
            return i
        k, b = divmod(a, p)
        for j in count(-k):
            if b not in aset:
                aset.add(b)
                a, p = b, nextprime(p)
                c += j
                break
            b += p # Chai Wah Wu, Oct 27 2023

Crossrefs

Cf. A064290, A364054, A366912.

Sequence in context: A098548 A076963 A081871 * A329573 A291163 A180743

Adjacent sequences: A366910 A366911 A366912 * A366914 A366915 A366916

Keyword

nonn,more

Author

Rémy Sigrist, Oct 27 2023

Extensions

a(29) from Chai Wah Wu, Oct 27 2023

a(30)-a(31) from Chai Wah Wu, Oct 28 2023

Status

approved