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 A175557 #15 Jul 23 2012 13:31:57 %S A175557 5,2,5,41,3,2,2,2,17,13,11,89,7,5,5,5,41,3,3,347,3,3,3,29,2,2,2,2, %T A175557 26041,2,2,2,23,2,2,2,2,2,17,13,13,1201,11,11,107,919,89,7,7,7,7,7,7, %U A175557 61,5,5,5,5,5,5,5,5,5,5,5,5,41,4111,3 %N A175557 Prime preperiodic part of the decimal expansion of 1/k as k runs through A065502. %C A175557 Primes in A175555 in the order of appearance. %C A175557 Multiples of 2 or 5 generate a quotient with a preperiodic sequence of digits, for example 1/24 = 0.041666666..., and 41 is the decimal form of the preperiodic part. %C A175557 The corresponding values of n are: 2, 5, 20, 24, 28, 36, 44, 50, 56, 72, 88, 112, 136, 168, 184, ... %D A175557 H. Rademacher and O. Toeplitz, Von Zahlen und Figuren (Springer 1930, reprinted 1968), ch. 19, 'Die periodischen Dezimalbrueche'. %e A175557 The prime 347 is in the sequence because 1/288 = .00347222222222222222... %e A175557 The prime 1201 is in the sequence because 1/832 =.001201 923076 923076 ... %p A175557 for n from 1 do %p A175557 p := A175555(n) ; %p A175557 if isprime(p) then %p A175557 print(p) ; %p A175557 end if; %p A175557 end do: # _R. J. Mathar_, Jul 22 2012 %Y A175557 Cf. A175555, A036275, A065502. %K A175557 nonn,base %O A175557 1,1 %A A175557 _Michel Lagneau_, Jun 30 2010