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A305719 Numbers whose squares have the same first and last digits. 8
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified May 23 08:38 EDT 2022. Contains 353961 sequences. (Running on oeis4.)