A116324 Numbers k such that k * (k+5) gives the concatenation of two numbers m and m+5.
31, 65, 42754, 57242, 75424, 425073, 574923, 979529, 4301394, 5698602, 7028667, 4925000748, 5074999248, 7748266575, 8511881485, 8814851185, 7059602159673, 7106167933829, 7439286611622, 7485852385778, 46791112884926
Offset: 1
Links
- Robert Israel, Table of n, a(n) for n = 1..5283
Programs
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Maple
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