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.

A281940 Least k such that k^n + 1 is the product of n distinct primes (k > 0).

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%I A281940 #21 Mar 12 2017 06:10:41
%S A281940 1,3,9,43,46,47,245,1697,109,565,3938,3255,30089,18951,2217
%N A281940 Least k such that k^n + 1 is the product of n distinct primes (k > 0).
%C A281940 Corresponding values of k^n + 1 are 2, 10, 730, 3418802, 205962977, 10779215330, ...
%e A281940 a(3) = 9 because 9^3 + 1 = 2 * 5 * 73 and 9 is the least number with this property.
%o A281940 (PARI) a(n) = my(k=1); while (!issquarefree(k^n+1) || omega(k^n+1) != n, k++); k;
%Y A281940 Cf. A001597, A005117, A216765, A280005.
%K A281940 nonn,more
%O A281940 1,2
%A A281940 _Altug Alkan_, Feb 24 2017
%E A281940 a(14)-a(15) from _Giovanni Resta_, Mar 10 2017