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.
%I A221849 #16 Jan 31 2013 16:48:48 %S A221849 1,4,25,149,1101,8489,69978,596022,5179467,45811178 %N A221849 Number of primes of the form (x+1)^5 - x^5 with x <= 10^n. %C A221849 Number of primes equal to the difference of two consecutive fifth powers (x+1)^5 - x^5 = 5x(x+1)(x^2+x+1)+1 (A121616) with x <= 10^n. Values of x = A121617. Sequence of number of primes of the form (x+1)^5 - x^5 with x <= 10^n have similar characteristics to similar sequences for natural primes and cuban primes (A221794). %t A221849 fQ[n_] := PrimeQ[(n + 1)^5 - n^5]; c = k = 0; Do[ While[k < 10^n + 1, If[ fQ@ k, c++]; k++]; Print[{n, c}], {n, 9}] (* _Robert G. Wilson v_, Jan 31 2013 *) %K A221849 nonn,base %O A221849 0,2 %A A221849 _Vladimir Pletser_, Jan 26 2013 %E A221849 a(7) - a(9) from _Robert G. Wilson v_, Jan 31 2013