A073537 Rearrangement of cubes such that the sum of two consecutive terms + 1 is a prime.

1, 27, 729, 2197, 1331, 6859, 24389, 343, 3375, 9261, 59319, 35937, 15625, 12167, 29791, 125, 4913, 79507, 19683, 389017, 91125, 166375, 132651, 117649, 185193, 2460375, 50653, 42875, 300763, 250047, 753571, 148877, 205379, 68921, 226981

Offset

1,2

Links

Sean A. Irvine, Table of n, a(n) for n = 1..1000

Prog

(Python)
from sympy import isprime
from itertools import count, islice
def agen(): # generator of terms
    rset, an, r, m = set(), 1, 1, 3
    while True:
        yield an
        rset.add(r)
        r = next(k for k in count(m, 2) if k not in rset and isprime(k**3 + an + 1))
        an = r**3
        while m in rset: m += 2
print(list(islice(agen(), 35))) # Michael S. Branicky, Dec 03 2024

Crossrefs

Cf. A000578.

Sequence in context: A171332 A097781 A223656 * A016947 A223790 A223976

Adjacent sequences: A073534 A073535 A073536 * A073538 A073539 A073540

Keyword

nonn

Author

Jason Earls, Aug 27 2002

Status

approved