A116096 Numbers k such that k concatenated with k-9 gives the product of two numbers which differ by 4.

21, 30, 902406, 959721, 6040059046, 6242406405, 9842410005, 9900249006, 15033519988494, 17250863148969, 22499666270469, 27632040031654, 34182546327286, 37487353123861, 52213551379230, 74230108225630

Offset

1,1

Comments

If k-9 has d digits, the concatenation is k//k-9 = 10^d*k+k-9 = m*(m+4), therefore k//k-5 = 10^d*k+k-5 = (m+2)^2, so there is a large overlap or equality with A115433. - R. J. Mathar, May 22 2026

Links

Table of n, a(n) for n=1..16.

Example

9900249006//9900248997 = 9949999499 * 9949999503, where // denotes concatenation.

Crossrefs

Cf. A115433, A116095, A116097, A116104, A116227.

Sequence in context: A318349 A228142 A276756 * A116116 A115433 A079394

Adjacent sequences: A116093 A116094 A116095 * A116097 A116098 A116099

Keyword

nonn,base

Author

Giovanni Resta, Feb 06 2006

Status

approved