A152070 Squares which form nonzero squares when their reversal is subtracted from them.

6300100, 7502121, 16654561, 57942544, 74753316, 696379321, 1185424900, 2176315801, 16960113361, 21735899761, 44504965444, 52141439025, 95610824100, 105593152401, 189565322881, 213454164121, 293481144121, 527475375625

Offset

1,1

Links

Table of n, a(n) for n=1..18.

Example

a(2) = 2739^2 = 7502121 => 7502121 - 1212057 = 6290064 = 2508^2.

Mathematica

nzsQ[n_]:=Module[{c=Sqrt[n-FromDigits[Reverse[IntegerDigits[n]]]]}, c!=0 && IntegerQ[c]]; Select[Range[750000]^2, nzsQ] (* Harvey P. Dale, Aug 03 2013 *)

Prog

(PARI) reverse(expr)=my(v=Vec(Str(expr)), n=length(v)); concat(vector(n, i, v[n-i+1])); lista(nn) = {for (n=1, nn, if (issquare(n), rn = eval(reverse(n)); if (n!= rn && issquare(n-rn), print1(n, ", "))); ); } \\ Michel Marcus, Jun 02 2013

Crossrefs

Sequence in context: A138941 A251379 A203894 * A147531 A018895 A178135

Adjacent sequences: A152067 A152068 A152069 * A152071 A152072 A152073

Keyword

nonn,base

Author

Gaurav Kumar, Jul 24 2009

Extensions

Definition clarified by Michel Marcus, Jun 02 2013

Status

approved