A116345
Numbers k such that k*(k+6) gives the concatenation of two numbers m and m+8.
Original entry on oeis.org
41, 54, 40354308, 59645687, 39704957106129738595969799927611, 44505281604832422780051712184760, 45053875613995255103944518907120, 54946124386004744896055481092875, 55494718395167577219948287815235, 60295042893870261404030200072384, 68683652917306421895276391964227
Offset: 1
59645687 * 59645693 = 35576083//35576091, where // denotes concatenation.
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f:= proc(d) local R;
R:= map(rhs@op,{msolve(x^2=17,10^d+1)});
R:= map(t -> (t-3) mod (10^d+1), R);
op(select(proc(t) local m; m:= (t*(t+6)-8)/(10^d+1)+8; m >= 10^(d-1) and m < 10^d end proc, R));
end proc;
sort(convert({seq(f(i),i=1..50)},list)); # Robert Israel, Jan 17 2017
A116215
Numbers k such that k concatenated with k+8 gives the product of two numbers which differ by 7.
Original entry on oeis.org
92, 180, 332, 486, 536, 9720, 13220, 40502, 941486, 2066120, 2975202, 77854680, 123250136, 162423540, 243964010, 256109750, 356387462, 421110162, 542936282, 547361900, 587114192, 591715970, 685172036, 734693886
Offset: 1
A116340
n times n+7 gives the concatenation of two numbers m and m+7.
Original entry on oeis.org
2, 33, 61, 805, 4779, 5215, 7407, 48208887, 51791107, 77620652, 4291816089, 4482541431, 5517458563, 5708183905, 9036996877, 9737360644, 3579205562000136225339579332, 3939042613182345526485238180
Offset: 1
A116347
n times n+9 gives the concatenation of two numbers m and m+8.
Original entry on oeis.org
345, 647, 829, 878, 933, 33180, 42271, 57721, 66812, 316429537030539, 319485532390187, 328611858418903, 332707864512186, 339600869407914, 347417506407134, 355879196889561, 370588838784509, 383811170906508
Offset: 1
66812 * 66821 = 44644//44652, where // denotes concatenation.
A116353
Numbers k such that k*(k+7) gives the concatenation of two numbers m and m+9.
Original entry on oeis.org
27, 67, 3416102887775247376839416334668636, 3756559953325598880263233435801765, 4313503800489302411917772257282209
Offset: 1
67 * 74 = 49//58, where // denotes concatenation.
Showing 1-5 of 5 results.