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 A135770 Numbers whose square is such that another square can be obtained by a cyclic permutation of the digits (excluding leading zeros). 1
 12, 14, 16, 21, 25, 31, 108, 122, 128, 129, 192, 196, 216, 221, 245, 247, 258, 294, 408, 463, 465, 486, 522, 604, 661, 694, 789, 804, 918, 933, 948, 981 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS This is a subsequence of { sqrt(A034289(n)) }, or equivalently, { a(n)^2 } is a subsequence of A034289. Cf. A135780 for more remarks. LINKS FORMULA a(n)=sqrt(A135780(n)) EXAMPLE a(1) = 12 since 12^2 = 144 is the least square such that a cyclic permutation of its decimal digits is again a square, namely 441 = 21^2. See A135780 for more explanations. PROG (PARI) for(n=1, 10^8, (t=n^2)/* %10 || next <= this would exclude terms with trailing '0's */; found=0; for(j=1, k=#Str(t)-1, t=divrem(t, 10); t[2] || (t=t[1]) && next /* <= this excludes leading '0's */; issquare(t=t[1]+10^k*t[2]) || next; /* t%10 || next; <= would exclude permutations with trailing '0's */ print1( if(found, "<<<"/* mark multiple permutations: this never happens */, found=1; n)", "))) CROSSREFS Cf. A135780 (the squares), A034289 (allowing arbitrary permutations). Sequence in context: A163622 A159251 A208156 * A091989 A078417 A107835 Adjacent sequences:  A135767 A135768 A135769 * A135771 A135772 A135773 KEYWORD base,easy,nonn AUTHOR M. F. Hasler, following ideas from David W. Wilson, Jan 31 2008 STATUS approved

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Last modified June 24 06:17 EDT 2021. Contains 345416 sequences. (Running on oeis4.)