A358880 Squares of the form k + reverse(k) for at least one k.

4, 16, 121, 484, 625, 1089, 10201, 14641, 19881, 40804, 49284, 69696, 91809, 94249, 203401, 698896, 1002001, 1234321, 1490841, 1517824, 4008004, 4276624, 4460544, 4937284, 5313025, 6325225, 6895876, 6948496, 7706176, 9018009, 15665764, 15776784, 16120225

Offset

1,1

Links

Table of n, a(n) for n=1..33.

Formula

a(n) = A356648(n)^2. - Michel Marcus, Dec 25 2022

Example

56 + reverse(56) = 56 + 65 = 121 = 11^2, so 121 is a term.

Prog

(Python)
from math import isqrt
def aupto(lim): return sorted(set(t for t in (k + int(str(k)[::-1]) for k in range(1, lim+1)) if t <= lim and isqrt(t)**2 == t))
print(aupto(10**7)) # Michael S. Branicky, Dec 25 2022

Crossrefs

Cf. A000290, A067030, A356648.

Sequence in context: A339200 A087335 A204573 * A306561 A226102 A094356

Adjacent sequences: A358877 A358878 A358879 * A358881 A358882 A358883

Keyword

nonn,base

Author

Jon E. Schoenfield, Dec 04 2022

Status

approved