A116160 Numbers k such that k concatenated with itself gives the product of two numbers which differ by 7.

4, 94, 210, 294, 994, 5880, 9994, 52888, 99994, 127044, 414180, 999994, 8264470, 9999994, 12456750, 41868508, 99999994, 112670544, 441341880, 468144040, 669421494, 702338994, 715976338, 750005718, 960645294, 999999994

Offset

1,1

Comments

If k has d digits, the concatenation is k//k = 10^d*k+k = m*(m+7), therefore k//k-8 = 10^d*k+k-8 = (m-1)*(m+8), so there is a large overlap with A116109. - R. J. Mathar, May 22 2026

Links

Table of n, a(n) for n=1..26.

Crossrefs

Cf. A020338, A116152, A116159, A116161, A116167, A116291.

Sequence in context: A387813 A202899 A030246 * A376419 A321221 A116291

Adjacent sequences: A116157 A116158 A116159 * A116161 A116162 A116163

Keyword

nonn,base

Author

Giovanni Resta, Feb 06 2006

Status

approved