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A325152 Numbers whose squares can be expressed as the product of a number and its reversal. 0
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 20, 22, 30, 33, 40, 44, 50, 55, 60, 66, 70, 77, 80, 88, 90, 99, 100, 101, 110, 111, 121, 131, 141, 151, 161, 171, 181, 191, 200, 202, 212, 220, 222, 232, 242, 252, 262, 272, 282, 292, 300, 303, 313, 323, 330, 333, 343, 353, 363, 373, 383, 393, 400, 403, 404, 414, 424, 434 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

The corresponding squares are in A325148 and the numbers k such that k * rev(k) is a square are in A306273.

The squares of the first 47 terms of this sequence (from 0 to 242) can be expressed as the product of a number and its reversal in only one way; then a(48) = 252 and 252^2 = 252 * 252 = 144 * 441.

The first 65 terms of this sequence (from 0 to 400) are exactly the first 65 terms of A061917; then a(66) = 403, non-palindrome, is the first term of the sequence A325151.

LINKS

Table of n, a(n) for n=1..70.

FORMULA

a(n) = sqrt(A325148(n)).

EXAMPLE

One way: 20^2 = 400 = 200 * 2.

Two ways: 2772^2 = 7683984 = 2772 * 2772 = 1584 * 4851.

Three ways: 2520^2 = 14400 * 441 = 25200 * 252 = 44100 * 144.

403 is a member since 403^2 = 162409 = 169*961 (note that 403 is not a member of A281625).

CROSSREFS

Cf. A325148, A325149, A083408, A325150, A307019.

Cf. also A061917, A325151.

Similar to but different from A281625.

Sequence in context: A084050 A281625 A169824 * A061917 A125289 A180482

Adjacent sequences:  A325149 A325150 A325151 * A325153 A325154 A325155

KEYWORD

nonn,base

AUTHOR

Bernard Schott, Apr 11 2019

STATUS

approved

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Last modified August 4 09:03 EDT 2020. Contains 336201 sequences. (Running on oeis4.)