A110460 Least multiple of n such that every concatenation a(1)...a(i) for 1 <= i <= n is a perfect square.

1, 6, 9, 744, 4179600, 8448511339584, 5768007101259200000000000049, 5174534068654382362457957919012519218990703784333328400, 2738806678866818978778889262772030983678218158753649709561749318814684327986697592167893627634348717226004356

Offset

1,2

Links

Table of n, a(n) for n=1..9.

Example

1, 16, 169, 169744 are all squares. [corrected by Harvey P. Dale, Aug 06 2019]

Prog

(PARI) f(n, num) = local(d, x); d = 1; while (1, x = sqrtint(num*10^d + 10^(d - 1) - 1) + 1; while (x^2 < (num + 1)*10^d && (x^2%10^d)%n, x++); if (x^2 < (num + 1)*10^d, return([x^2, x^2%10^d])); d++);
num = 0; for (n = 1, 10, p = f(n, num); print1(p[2], ", "); num = p[1]); \\ David Wasserman, Dec 03 2008

Crossrefs

Cf. A061110.

Sequence in context: A376382 A376386 A061110 * A159190 A236766 A004075

Adjacent sequences: A110457 A110458 A110459 * A110461 A110462 A110463

Keyword

base,nonn

Author

Amarnath Murthy, Aug 04 2005

Extensions

More terms from David Wasserman, Dec 03 2008

Clarified definition. - N. J. A. Sloane, Sep 25 2023

Status

approved