A116499 -id:A116499 - cp's OEIS frontend

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

Neville Holmes, Jun 08 2018

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

Cf. A227858, A116499, A116501.

Cf. A123912, A186438.

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

for(n=1, 10^3, my(d=digits(n^2)); if( d[1]==d[#d], print1(n,", "))); \\ Joerg Arndt, Jun 10 2018

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

A116501 Numbers k such that the base-10 representation of k^2 has the structure dmdmd, where d is a single digit and m is a string of digits.

Original entry on oeis.org

264, 238165, 309097, 1052631579, 1104579631, 2076555028, 2105263158, 2209159262, 3004048583, 3157894737, 30762132977, 107438016531, 214876033062, 10909090909091, 21818181818182, 1001889106154509, 1047612381019049, 1109550442957111, 1113036341252109, 1123107893966631, 1136632365773631, 1168831168831171

Offset: 1

Giovanni Resta, Feb 18 2006

			309097^2 = 9[5540]9[5540]9.

Max Alekseyev, Table of n, a(n) for n = 1..10000

Cf. A116499, A116502.

Terms a(17) onward from Max Alekseyev, Oct 14 2024

A116500 Squares with structure dmmd, where d is a single digit and m a string of digits.

Original entry on oeis.org

4040609404060944, 603783587037835876, 617639516153625555176395161536255556, 680188481201573219801884812015732196, 1761443640995119484476144364099511948441, 61481953823648396265074271481953823648396265074276, 601361184010565719927255118499013611840105657199272551184996

Offset: 1

Giovanni Resta, Feb 18 2006

			785900449264170834^2 = a(3) = 6[17639516153625555][17639516153625555]6.

Cf. A116499, A116502.

a(n) = A116499(n)^2.

cp's OEIS Frontend

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

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A116501 Numbers k such that the base-10 representation of k^2 has the structure dmdmd, where d is a single digit and m is a string of digits.

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A116500 Squares with structure dmmd, where d is a single digit and m a string of digits.

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