A062689 Smallest square that contains the digits of n in its exact middle.

0, 1, 121, 12321, 4, 256, 169, 576, 289, 9, 8100, 2116, 361201, 3136, 181476, 1156, 16, 101761, 5184, 281961, 2209, 9216, 1225, 182329, 3249, 25, 292681, 192721, 8281, 1296, 2304, 183184, 5329, 343396, 203401, 4356, 36, 223729, 173889, 7396, 2401

Offset

0,3

Links

Michael S. Branicky, Table of n, a(n) for n = 0..9999

Example

8100 is the smallest square that contains 10 in its exact center.

Prog

(Python)
def centered(s, t):
    q, r = divmod(len(t)-len(s), 2)
    return r == 0 and t[q:].startswith(s)
def a(n):
    k, target = 0, str(n)
    while not centered(target, str(k**2)): k += 1
    return k**2
print([a(n) for n in range(43)]) # Michael S. Branicky, Feb 16 2022

Crossrefs

Cf. A062690.

Sequence in context: A006061 A079215 A137466 * A057139 A321687 A002477

Adjacent sequences: A062686 A062687 A062688 * A062690 A062691 A062692

Keyword

base,easy,nonn

Author

Erich Friedman, Jul 04 2001

Extensions

Corrected and extended by Harvey P. Dale, Jul 21 2001

a(40) from Bernard Schott, Feb 16 2022

Status

approved