A373799 Index of n-th prime in A374965.

2, 5, 9, 14, 19, 22, 25, 36, 38, 43, 47, 51, 56, 65, 72, 74, 76, 97, 100, 102, 105, 107, 110, 112, 115, 122, 125, 128, 130, 238, 255, 260, 272, 284, 286, 290, 293, 296, 300, 316, 325, 331, 562, 565, 567, 575, 578, 607, 610, 612, 617, 627, 632, 649, 651, 654, 866, 875, 878

Offset

1,1

Links

N. J. A. Sloane, Table of n, a(n) for n = 1..290 (Terms 1 through 289 were obtained using Harvey P. Dale's MMA program for A373798. For a(290), see A375028.)

N. J. A. Sloane, A Nasty Surprise in a Sequence and Other OEIS Stories, Experimental Mathematics Seminar, Rutgers University, Oct 10 2024, Youtube video; Slides [Mentions this sequence]

Example

The fifth prime in order of appearance in A374965 is A375028(5) = 751 = A374965(19), so a(5) = 19.

Prog

(Python)
from itertools import count, islice
from sympy import isprime, nextprime
def A373799_gen(): # generator of terms
    a, p = 1, 3
    for i in count(1):
        if isprime(a):
            yield i
            a = p-1
        else:
            a = (a<<1)+1
        p = nextprime(p)
A373799_list = list(islice(A373799_gen(), 20)) # Chai Wah Wu, Jul 29 2024

Crossrefs

Cf. A373798 (first differences), A374965, A375028.

Sequence in context: A161767 A235333 A060139 * A266899 A112265 A025281

Adjacent sequences: A373796 A373797 A373798 * A373800 A373801 A373802

Keyword

nonn

Author

Harvey P. Dale and N. J. A. Sloane, Jul 28 2024

Status

approved