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 A379157 #8 Dec 23 2024 09:56:22 %S A379157 3,4,7,9,13,16,23,27,31,32,47,49,61,64,79,81,113,125,127,128,167,169, %T A379157 241,243,251,256,283,289,337,343,359,361,509,512,523,529,619,625,727, %U A379157 729,839,841,953,961,1021,1024,1327,1331,1367,1369,1669,1681,1847,1849 %N A379157 Prime powers p such that the interval from p to the next prime power contains a unique prime number. %F A379157 a(n) = A246655(A379155(n)). %e A379157 The next prime power after 32 is 37, with interval (32,33,34,35,36,37) containing just one prime 37, so 32 is in the sequence. %t A379157 v=Select[Range[100],PrimePowerQ] %t A379157 nextpripow[n_]:=NestWhile[#+1&,n+1,!PrimePowerQ[#]&] %t A379157 Select[v,Length[Select[Range[#,nextpripow[#]],PrimeQ]]==1&] %Y A379157 For no primes we have A068315/A379156, for perfect powers A116086/A274605. %Y A379157 The previous instead of next prime power we have A175106. %Y A379157 For perfect powers instead of prime powers we have A378355. %Y A379157 The positions of these prime powers (in A246655) are A379155. %Y A379157 A000015 gives the least prime power >= n. %Y A379157 A000040 lists the primes, differences A001223. %Y A379157 A000961 lists the powers of primes, differences A057820. %Y A379157 A031218 gives the greatest prime power <= n. %Y A379157 A065514 gives the greatest prime power < prime(n), difference A377289. %Y A379157 A246655 lists the prime powers. %Y A379157 A366833 counts prime powers between primes, see A053607, A304521. %Y A379157 A366835 counts primes between prime powers, for perfect powers A080769. %Y A379157 Cf. A046933, A067871, A080101, A178700, A345531, A377281, A377287, A377434, A378374. %K A379157 nonn %O A379157 1,1 %A A379157 _Gus Wiseman_, Dec 22 2024