A034990 a(n)^2 is smallest square starting with a string of n 7's.

27, 88, 882, 8819, 278886, 881917, 8819171, 8819171, 2788866754, 2788866755, 27888667551, 881917103688, 8819171036882, 278886675511358, 2788866755113584, 27888667551135851, 88191710368819686, 278886675511358516, 8819171036881968635, 8819171036881968635

Offset

1,1

References

David Wells, 'Curious and Interesting Numbers', Penguin Books 1988, p. 184.

Links

Table of n, a(n) for n=1..20.

Example

a(5) = 278886^2 = {77777}400996.

Crossrefs

Cf. A034991.

Sequence in context: A262367 A007266 A098320 * A090949 A043434 A044214

Adjacent sequences: A034987 A034988 A034989 * A034991 A034992 A034993

Keyword

nonn,base

Author

Patrick De Geest, Nov 15 1998

Extensions

More terms from Francisco Salinas (franciscodesalinas(AT)hotmail.com), Dec 23 2001

a(18) corrected and a(19), a(20) added by John Tomko, Nov 14 2006

Status

approved