A046233 Numbers whose cube is palindromic in base 5.

0, 1, 6, 26, 126, 626, 3126, 15626, 78126, 390626, 1953126, 9765626, 48828126, 244140626, 1220703126, 6103515626, 30517578126, 152587890626, 762939453126, 3814697265626, 19073486328126, 95367431640626, 476837158203126

Offset

1,3

Comments

Note that '626' is itself palindromic.

Contains all A034474(n), n>=1, as a subset because (5^n+1)^3=5^(3n)+3*5^(2n)+3*5^n+1 is a symmetric string 100..00300..00300..001 in base 5. [R. J. Mathar, Jul 31 2008]

Links

Table of n, a(n) for n=1..23.

Patrick De Geest, World!Of Numbers

Prog

(PARI) isok(k) = my(d=digits(k^3, 5)); Vecrev(d) == d; \\ Michel Marcus, Aug 02 2022
(Python)
from itertools import count, islice
from sympy.ntheory import is_palindromic as ispal
def agen(start=0): yield from (k for k in count(start) if ispal(k**3, 5))
print(list(islice(agen(), 10))) # Michael S. Branicky, Aug 02 2022

Crossrefs

Cf. A034474, A046234.

Sequence in context: A233075 A307331 A298625 * A140231 A339685 A364744

Adjacent sequences: A046230 A046231 A046232 * A046234 A046235 A046236

Keyword

nonn,base,more

Author

Patrick De Geest, May 15 1998

Extensions

More terms from Megan Francis (mkf5011(AT)psu.edu), Nov 15 2005

Status

approved