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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
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
Sequence in context: A302310 A295958 A049083 * A002778 A028816 A316187
KEYWORD
nonn,base,easy
AUTHOR
Neville Holmes, Jun 08 2018
STATUS
approved

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Last modified July 24 02:45 EDT 2024. Contains 374575 sequences. (Running on oeis4.)