A115539 Numbers k such that the concatenation of k with 5*k gives a square.

2040816326530612245, 8163265306122448980, 18367346938775510205, 265008112493239588967009194159005, 346133044889129259058950784207680, 438074634937804218496484586262845, 540832882639264467279610600324500

Offset: 1

Author

Giovanni Resta, Jan 25 2006

Keywords

• nonn
• base

Examples

			2040816326530612245_10204081632653061225 = 14285714285714285715^2.
		

Crossrefs

Cf. A102567, A106497, A115527 - A115556.