A305719 Numbers whose squares have the same first and last digits.

1, 2, 3, 11, 22, 26, 39, 41, 68, 75, 97, 101, 109, 111, 119, 121, 129, 131, 139, 141, 202, 208, 212, 218, 222, 225, 235, 246, 254, 256, 264, 303, 307, 313, 319, 321, 329, 331, 339, 341, 349, 351, 359, 361, 369, 371, 379, 381, 389, 391, 399, 401, 409, 411, 419, 421, 429, 431, 439, 441, 638

Offset

1,2

Links

Table of n, a(n) for n=1..61.

Example

For k = 11, k^2 = 121;
for k = 26, k^2 = 676.

Mathematica

Select[Range[638], (d = IntegerDigits[#^2]; d[[1]] == d[[-1]]) &] (* Giovanni Resta, Jun 25 2018 *)

Prog

(PARI) for(n=1, 10^3, my(d=digits(n^2)); if( d[1]==d[#d], print1(n, ", "))); \\ Joerg Arndt, Jun 10 2018
(Python)
def ok(n): s = str(n*n); return s[0] == s[-1]
print(list(filter(ok, range(1, 639)))) # Michael S. Branicky, Jul 16 2021

Crossrefs

Cf. A227858, A116499, A116501.

Sequence in context: A302310 A295958 A049083 * A002778 A028816 A316187

Adjacent sequences: A305716 A305717 A305718 * A305720 A305721 A305722

Keyword

nonn,base,easy

Author

Neville Holmes, Jun 08 2018

Status

approved