OFFSET
1,1
COMMENTS
Square roots of the squares in A067030.
LINKS
Hugo Pfoertner, Table of n, a(n) for n = 1..2253, using results from participants Sebastian and l4m2 at the Code Golf challenge.
Nicolay Avilov, Problem 2422. Mirror numbers (in Russian).
Code Golf Stack Exchange, RADD decomposition of an integer, coding challenge started Jan 01 2023.
FORMULA
a(n) = sqrt(A358880(n)). - Michel Marcus, Dec 25 2022
EXAMPLE
4 is a term since 4^2 = 16 = 8 + 8;
11 is a term since 11^2 = 121 = 29 + 92 is sum of k=29 and its reversal 92;
22 is a term since 22^2 = 484 = 143 + 341;
10201 is a term since 10201^2 = 104060401 = 100030400 + 4030001.
PROG
(PARI) L=vectorsmall(100000);
\\ Takes a few minutes of CPU time
for (k=1, 2*10^8, my(d=digits(k), r=fromdigits(Vecrev(d)), s); if (issquare(k+r, &s), L[s]=1));
for (k=1, 21000, if(L[k], print1(k, ", "))) \\ Hugo Pfoertner, Dec 13 2022
(C++, Haskell) See Code Golf link.
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Nicolay Avilov, data a(10)-a(37) from Oleg Sorokin, Dec 10 2022
EXTENSIONS
a(38) and beyond from Hugo Pfoertner, Dec 12 2022
STATUS
approved