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 A278419 #17 Feb 16 2025 08:33:37
%S A278419 1,0,2,7,2,9,4,2,6,3,8,6,0,1,5,0,7,4,8,9,7,6,6,2,4,8,4,6,8,4,5,7,4,3,
%T A278419 2,8,9,7,8,9,5,7,4,1,7,0,4,1,4,3,4,9,5,9,1,9,0,3,5,9,9,5,3,8,6,4,0,2,
%U A278419 0,6,6,1,6,2,5,8,1,8,3,5,0,2,5,5,0,8,2,1,6,7,3,0,7,2,3,6,2,6,9,7,5,9,9,4
%N A278419 Decimal expansion of sum of cubes of reciprocals of nonprime numbers.
%H A278419 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/ZetaFunction.html">Zeta Function</a>.
%H A278419 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/PrimeZetaFunction.html">Prime Zeta Function</a>.
%F A278419 Sum_{n>=1} 1/n^3 - Sum_{n>=1} 1/prime(n)^3.
%F A278419 Equals zeta(3) - primezetaP(3).
%F A278419 Sum of cubes of reciprocals of composite numbers = zeta(3) - primezetaP(3) - 1 = 0.02729426386...
%e A278419 1.0272942638601507489766248468457432897895741704143495919035995386402...
%t A278419 RealDigits[Zeta[3] - PrimeZetaP[3], 10, 104][[1]]
%o A278419 (PARI) zeta(3) - sumeulerrat(1/p, 3) \\ _Amiram Eldar_, Mar 19 2021
%Y A278419 Cf. A275647.
%K A278419 nonn,cons
%O A278419 1,3
%A A278419 _Jean-François Alcover_, Nov 21 2016