cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A380405 Squares k such that there are no primes between k and the nearest cube that is not k.

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%I A380405 #41 Jan 28 2025 13:56:30
%S A380405 9,25,121,32761,79524,97344
%N A380405 Squares k such that there are no primes between k and the nearest cube that is not k.
%C A380405 There are no other terms < 2*10^30.
%e A380405 121 is a term because it is a square and there are no primes between 123 and 125, its nearest cube.
%t A380405 b[n_] := If[IntegerQ@Sqrt@n, 0, p = NextPrime[n^3];
%t A380405   q = Ceiling[Sqrt[NextPrime[p, -1]]];  If[q^2 >= p, 0, q]];
%t A380405  Select[Array[b@# &, 1000], # > 0 &]^2
%Y A380405 Cf. A053706, A380521, A380522, A380523, A078933.
%K A380405 nonn,hard,more
%O A380405 1,1
%A A380405 _Zhining Yang_, Jan 26 2025