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A116267 Numbers k such that k*(k+4) gives the concatenation of two numbers m and m-3.

%I A116267 #16 Feb 19 2024 19:45:35
%S A116267 8,98,426,571,725,844,998,7808,9998,36363,63634,99998,326732,673265,
%T A116267 999998,4545452,5454545,9999998,47058821,52941176,99999998,331983805,
%U A116267 332667332,384615384,422892896,475524475,524475522,577107101,615384613,667332665,668016192,719964244
%N A116267 Numbers k such that k*(k+4) gives the concatenation of two numbers m and m-3.
%H A116267 Chai Wah Wu, <a href="/A116267/b116267.txt">Table of n, a(n) for n = 1..10000</a>
%o A116267 (Python)
%o A116267 from itertools import count, islice
%o A116267 from sympy import sqrt_mod
%o A116267 def A116267_gen(): # generator of terms
%o A116267     for j in count(0):
%o A116267         b = 10**j
%o A116267         a = b*10+1
%o A116267         for k in sorted(sqrt_mod(1,a,all_roots=True)):
%o A116267             if a*(b+3) <= k**2-1 < a*(a+2):
%o A116267                 yield k-2
%o A116267 A116267_list = list(islice(A116267_gen(),20)) # _Chai Wah Wu_, Feb 19 2024
%Y A116267 Cf. A116136, A116260, A116266, A116268, A116275.
%K A116267 nonn,base
%O A116267 1,1
%A A116267 _Giovanni Resta_, Feb 06 2006
%E A116267 a(29)-a(32) from _Chai Wah Wu_, Feb 19 2024