A115430 Numbers k such that the concatenation of k with k+9 gives a square.

216, 287, 515, 675, 1175, 4320, 82640, 960795, 1322312, 4049591, 16955015, 34602080, 171010235, 181964891, 183673467, 187160072, 321920055, 326530616, 328818032, 343942560, 470954312, 526023432, 528925616, 534830855

Offset

1,1

Comments

Also numbers k such that k concatenated with k+8 gives the product of two numbers which differ by 2.

Also numbers k such that k concatenated with k+5 gives the product of two numbers which differ by 4.

Links

Table of n, a(n) for n=1..24.

Example

82640_82649 = 90907^2.

Crossrefs

Cf. A030465, A102567, A115426, A115437, A115428, A115429, A115431, A115432, A115433, A115434, A115435, A115436, A115441.

Cf. A116172, A116168, A116344, A116112, A116193, A116173, A116323.

Sequence in context: A348609 A205191 A204650 * A278976 A179419 A224549

Adjacent sequences: A115427 A115428 A115429 * A115431 A115432 A115433

Keyword

base,nonn

Author

Giovanni Resta, Jan 24 2006

Extensions

Edited by N. J. A. Sloane, Apr 13 2007

Status

approved