A353731 a(n) = index where prime(n) appears in A352808.

2, 6, 4, 11, 18, 19, 16, 24, 45, 52, 63, 29, 30, 78, 122, 71, 123, 148, 46, 72, 53, 162, 96, 66, 100, 161, 243, 212, 194, 186, 394, 75, 86, 110, 114, 177, 204, 111, 254, 295, 273, 274, 494, 124, 167, 386, 338, 642, 339, 410, 347, 650, 351, 762, 159, 180, 195, 250, 191, 208, 225, 270, 284, 595, 340, 689, 290, 238, 732, 730, 258, 651, 696, 624, 749, 1062, 271, 311, 300, 326, 666, 625, 1006, 634, 1007, 1050, 269, 738, 759, 970, 898, 1443, 1122, 1123, 1139, 1570, 1483

Offset: 1

Author

N. J. A. Sloane, May 17 2022

Keywords

• nonn

Comments

Here prime(n) means the n-th prime in 2, 3, 5, 7, ..., not the n-th term of A352808 that happens to be a prime.

Links

• Michael S. Branicky, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A352808, A353732.

Programs

Python

from sympy import nextprime
from itertools import count, islice
def agen(): # generator of terms
    A352808lst = [0, 1]; A352808set = {0, 1}
    mink = p = 2
    for n in count(2):
        ahalf, k = A352808lst[n//2], mink
        while k in A352808set or k&ahalf: k += 1
        A352808lst.append(k); A352808set.add(k)
        while mink in A352808set: mink += 1
        while p in A352808set: yield A352808lst.index(p); p = nextprime(p)
print(list(islice(agen(), 76))) # Michael S. Branicky, May 17 2022

Formula

a(n) = k if A352808(k) = prime(n). - Michael S. Branicky, May 17 2022