A115442 Numbers whose square is the concatenation of two numbers k and k-2.

8, 7312, 8991, 32524, 67477, 76568, 4891730, 5108271, 8528094, 71588336, 98999901, 399659933007, 600340066994, 723627738227, 877712329768, 998999999001, 3485626998114, 3787100274614, 6212899725387, 6514373001887

Offset

1,1

Links

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

Example

8083_8081 = 8991^2.

Mathematica

Select[Table[Sqrt[k*10^IntegerLength[k]+k-2], {k, 4, 86*10^5}], IntegerQ] (* The program generates the first 9 terms of the sequence. *) (* Harvey P. Dale, Nov 02 2024 *)

Crossrefs

Cf. A030467, A106497, A115431, A115427, A115438, A115439, A115440, A115441, A115443, A115444, A115445, A115446, A115447.

Sequence in context: A354567 A356083 A278854 * A216936 A090494 A079656

Adjacent sequences: A115439 A115440 A115441 * A115443 A115444 A115445

Keyword

base,nonn

Author

Giovanni Resta, Jan 24 2006

Status

approved