A116098
Numbers k such that k concatenated with k-9 gives the product of two numbers which differ by 6.
Original entry on oeis.org
11, 101, 1001, 10001, 100001, 1000001, 10000001, 100000001, 1000000001, 10000000001, 13223140496, 20661157025, 29752066116, 40495867769, 52892561984, 66942148761, 82644628100, 100000000001, 1000000000001
Offset: 1
100000001//99999992 = 99999998 * 100000004, where // denotes
concatenation.
-
g:= proc(d) local r,c,a,b;
r:= mul(t[1],t=select(s -> s[2]::odd, ifactors(10^d+1)[2]))
c:= ceil((10^(d-1)+9)/r);
a:= isqrt(c);
if a^2 < c then a:= a+1 fi;
c:= floor((10^d+8)/r);
b:= isqrt(c);
if b^2 > c then b:= b-1 fi;
seq(r*y^2, y = a..b)
end proc:
seq(g(d),d=1..60); # Robert Israel, Aug 13 2018
A116105
Numbers k such that k concatenated with k-8 gives the product of two numbers which differ by 5.
Original entry on oeis.org
5303944, 6677714, 2070936216988528558, 2969428172738875624, 6685545813563350444, 8013829604553736451395958429212, 9724110515510343256451213152382
Offset: 1
A116096
Numbers k such that k concatenated with k-9 gives the product of two numbers which differ by 4.
Original entry on oeis.org
21, 30, 902406, 959721, 6040059046, 6242406405, 9842410005, 9900249006, 15033519988494, 17250863148969, 22499666270469, 27632040031654, 34182546327286, 37487353123861, 52213551379230, 74230108225630
Offset: 1
9900249006//9900248997 = 9949999499 * 9949999503, where // denotes concatenation.
A116228
n times n+5 gives the concatenation of two numbers m and m-9.
Original entry on oeis.org
96011, 3812029082958589067221817215312, 6187970917041410932778182784684, 3189731673290266386838927279556315880
Offset: 1
96011 * 96016 = 92185//92176, where // denotes concatenation.
Showing 1-4 of 4 results.
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