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A349309 Numbers k such that A254926(k) = A254926(k+1).

%I A349309 #11 Jan 24 2022 15:58:37
%S A349309 7,26,124,342,1330,2196,12166,24388,29790,79506,103822,148876,205378,
%T A349309 226980,300762,357910,493038,571786,1030300,1092726,1225042,2248090,
%U A349309 2685618,3307948,3442950,3869892,4657462,5177716,5735338,6967870,7645372,9393930,11089566,11697082
%N A349309 Numbers k such that A254926(k) = A254926(k+1).
%H A349309 Amiram Eldar, <a href="/A349309/b349309.txt">Table of n, a(n) for n = 1..100</a>
%e A349309 7 is a term since A254926(7) = A254926(8) = 7.
%t A349309 f[p_, e_] := If[e < 3, p^e, p^e - p^(e - 3)]; s[n_] := Times @@ f @@@ FactorInteger[n]; Select[Range[10^6], s[#] == s[# + 1] &]
%o A349309 (Python)
%o A349309 from math import prod
%o A349309 from itertools import count, islice
%o A349309 from sympy import factorint
%o A349309 def A349309_gen(startvalue=1): # generator of terms >= startvalue
%o A349309     a = prod(p**e - (p**(e-3) if e >= 3 else 0) for p, e in factorint(max(startvalue,1)).items())
%o A349309     for k in count(max(startvalue,1)):
%o A349309         b = prod(p**e - (p**(e-3) if e >= 3 else 0) for p, e in factorint(k+1).items())
%o A349309         if a == b:
%o A349309             yield k
%o A349309         a = b
%o A349309 A349309_list = list(islice(A349309_gen(),10)) # _Chai Wah Wu_, Jan 24 2022
%Y A349309 Cf. A254926.
%Y A349309 Similar sequences: A001274, A287055, A293184, A326403, A336673, A349307, A349308.
%K A349309 nonn
%O A349309 1,1
%A A349309 _Amiram Eldar_, Nov 14 2021