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.

A227000 Numbers k such that (k+1)^2-k^2 and (k+1)^3-k^3 are both prime.

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%I A227000 #10 Jul 30 2025 19:24:19
%S A227000 1,2,3,6,9,11,14,23,30,41,48,63,74,81,86,90,95,105,119,125,128,140,
%T A227000 153,156,158,165,179,186,191,209,216,219,224,233,245,251,296,303,308,
%U A227000 315,321,350,354,359,375,398,405,419,429,441,443,468,485,506,524,531,543,546,576
%N A227000 Numbers k such that (k+1)^2-k^2 and (k+1)^3-k^3 are both prime.
%e A227000 n=23; n+1=24; 24^2-23^2=47 and 24^3-23^3=1657.
%t A227000 Select[Range[576], PrimeQ[(# + 1)^2 - #^2] && PrimeQ[(# + 1)^3 - #^3] &] (* _T. D. Noe_, Jun 26 2013 *)
%o A227000 (PARI) forprime(p=3,1e3,n=p\2;if(isprime(3*n*(n+1)+1),print1(n", "))) \\ _Charles R Greathouse IV_, Jun 26 2013
%K A227000 nonn
%O A227000 1,2
%A A227000 _César Aguilera_, Jun 26 2013