A061110 a(1) = 1; a(n) = smallest number such that the concatenation a(1)a(2)...a(n) is a square.

1, 6, 9, 744, 41796, 60172924176, 8240010144800000000001, 82400101448000000000020000000000000000000001

Offset

1,2

Comments

The next term is too large to include.

a(n) is at most doubly exponential in n. Is there also a double exponential lower bound? - Charles R Greathouse IV, Sep 19 2012

Links

Table of n, a(n) for n=1..8.

A. Murthy, Exploring some new ideas on Smarandache type sets, functions and sequences, Smarandache Notions Journal Vol. 11 N. 1-2-3 Spring 2000.

Example

a(1) = 1, a(1)a(2) = 16 = 4^2, a(1)a(2)a(3) = 169 = 13^2, 169744 = 412^2.

Crossrefs

Cf. A061109, A051671. The actual squares are in A048557.

Sequence in context: A377391 A376382 A376386 * A110460 A159190 A236766

Adjacent sequences: A061107 A061108 A061109 * A061111 A061112 A061113

Keyword

base,nonn

Author

Amarnath Murthy, Apr 20 2001

Extensions

More terms from Larry Reeves (larryr(AT)acm.org), Jul 23 2001

Status

approved