A116159 Numbers k such that k concatenated with itself gives the product of two numbers which differ by 6.

5, 95, 216, 287, 515, 675, 995, 1175, 4320, 9995, 82640, 99995, 960795, 999995, 1322312, 4049591, 9999995, 16955015, 34602080, 99999995, 171010235, 181964891, 183673467, 187160072, 321920055, 326530616, 328818032

Offset

1,1

Comments

If k has d digits, the concatenation is k//k = 10^d*k+k = m*(m+6), therefore k//k-7 = 10^d*k+k-7 = (m-1)*(m+7), so there is a large overlap with A116113. - R. J. Mathar, May 22 2026

Links

Table of n, a(n) for n=1..27.

Crossrefs

Cf. A115429, A116158, A116160, A116173, A116290.

Sequence in context: A178018 A195854 A153227 * A054205 A116290 A274874

Adjacent sequences: A116156 A116157 A116158 * A116160 A116161 A116162

Keyword

nonn,base

Author

Giovanni Resta, Feb 06 2006

Status

approved