A061230 Numbers k such that k + the reversal of k is a square.
0, 2, 8, 29, 38, 47, 56, 65, 74, 83, 92, 110, 143, 164, 198, 242, 263, 297, 341, 362, 396, 440, 461, 495, 560, 594, 693, 792, 891, 990, 10100, 10148, 10340, 10395, 10403, 10683, 10908, 10980, 11138, 11330, 11385, 11673, 11970, 12128, 12320, 12375
Offset: 1
Examples
8 is a term as 8 + 8 = 16 = 4^2. 56 is a term as 56 + 65 = 121 = 11^2.
Links
- Michael S. Branicky, Table of n, a(n) for n = 1..10000 (terms 1..1000 from Paolo P. Lava)
Programs
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Maple
digrev:= proc(n) local L,i; L:= convert(n,base,10); add(L[-i]*10^(i-1),i=1..nops(L)) end proc: select(t -> issqr(t+digrev(t)),[$0..20000]); # Robert Israel, May 04 2015
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Mathematica
Select[Range[0,15000],IntegerQ[Sqrt[#+FromDigits[Reverse[ IntegerDigits[#]]]]]&] (* Harvey P. Dale, Apr 18 2011 *)
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PARI
isok(n) = issquare(n + fromdigits(Vecrev(digits(n)))); \\ Michel Marcus, Aug 04 2019
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Python
from math import isqrt def issquare(n): return isqrt(n)**2 == n def ok(n): return issquare(n + int(str(n)[::-1])) print([k for k in range(12376) if ok(k)]) # Michael S. Branicky, Dec 09 2022
Extensions
Corrected and extended by Patrick De Geest, May 28 2001
Edited by N. J. A. Sloane, Jul 24 2009