A116324
Numbers k such that k * (k+5) gives the concatenation of two numbers m and m+5.
Original entry on oeis.org
31, 65, 42754, 57242, 75424, 425073, 574923, 979529, 4301394, 5698602, 7028667, 4925000748, 5074999248, 7748266575, 8511881485, 8814851185, 7059602159673, 7106167933829, 7439286611622, 7485852385778, 46791112884926
Offset: 1
-
f:= proc(d) local S,R,r,s,m,n;
r:= 10^d+1;
S:= map(t -> rhs(op(t)), [msolve(n*(n+5)=5,r)]);
S:= select(proc(s) local t; t:= (s*(s+5)-5)/r; t+5 >= (r-1)/10 and t+5 < r-1 end proc, S);
op(sort(S));
end proc:
map(f, [$1..20]); # Robert Israel, Jun 21 2024
A116200
Numbers k such that k concatenated with k+6 gives the product of two numbers which differ by 5.
Original entry on oeis.org
210, 294, 5880, 52888, 127044, 414180, 8264470, 12456750, 41868508, 112670544, 441341880, 468144040, 669421494, 702338994, 715976338, 750005718, 960645294, 1491030294, 3768258010, 4783279044, 8505429358, 17105045530
Offset: 1
A116330
Numbers k such that k*(k+3) gives the concatenation of two numbers m and m+6.
Original entry on oeis.org
4, 85, 76982, 714689, 952313, 90438190, 96320543, 32980078899028, 34346653774237, 42816188292272, 42881990066487, 57118009933511, 57183811707726, 65653346225761, 67019921100970, 81321742742209
Offset: 1
96320543 * 96320546 = 92776472//92776478, where // denotes concatenation.
A116332
n times n+7 gives the concatenation of two numbers m and m+6.
Original entry on oeis.org
7041, 487249777146, 512750222848, 684330069117
Offset: 1
7041 * 7048 = 4962//4968, where // denotes concatenation.
A116338
n times n+5 gives the concatenation of two numbers m and m+7.
Original entry on oeis.org
700, 777, 791, 868, 42338, 57658, 96884, 44121667, 55878329, 85298138, 36680703009575609347721358494, 63319296990424390652278641502, 69346342454876071597336150482, 81501115172242572470460459684
Offset: 1
85298138 * 85298143 = 72757727//72757734, where // denotes
concatenation.
Showing 1-5 of 5 results.