A116200 Numbers k such that k concatenated with k+6 gives the product of two numbers which differ by 5.

210, 294, 5880, 52888, 127044, 414180, 8264470, 12456750, 41868508, 112670544, 441341880, 468144040, 669421494, 702338994, 715976338, 750005718, 960645294, 1491030294, 3768258010, 4783279044, 8505429358, 17105045530

Offset

1,1

Comments

Numbers k such that, if k+6 has d digits, k*(10^d+1) is the product of two numbers that differ by 7. - Robert Israel, Nov 24 2025

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Maple

N:= 12: # For terms k where k+6 has <= N digits
f:= proc(d) local x, C;
   C:= map(t -> subs(t, x), [msolve((x+6)*(x-1)=0, 10^d+1)]);
   C:= map(x -> (x+6)*(x-1)/(10^d+1), C);
   op(sort(select(x -> (x+6 >= 10^(d-1) and x + 6 < 10^d), C)))
end proc:
map(f, [$2..N]); # Robert Israel, Nov 24 2025

Crossrefs

Cf. A116193, A116172, A116147, A116207, A116331.

Sequence in context: A025392 A025383 A291715 * A125011 A119427 A127424

Adjacent sequences: A116197 A116198 A116199 * A116201 A116202 A116203

Keyword

nonn,base,look

Author

Giovanni Resta, Feb 06 2006

Status

approved