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 A005084 #19 Jun 21 2022 05:10:30 %S A005084 0,0,27,0,0,27,343,0,27,0,1331,27,0,343,27,0,0,27,6859,0,370,1331, %T A005084 12167,27,0,0,27,343,0,27,29791,0,1358,0,343,27,0,6859,27,0,0,370, %U A005084 79507,1331,27,12167,103823,27,343,0,27,0,0,27,1331,343,6886,0,205379,27,0,29791,370,0,0,1358,300763,0,12194,343,357911 %N A005084 Sum of cubes of primes = 3 mod 4 dividing n. %H A005084 Antti Karttunen, <a href="/A005084/b005084.txt">Table of n, a(n) for n = 1..10000</a> %F A005084 Additive with a(p^e) = p^3 if p = 3 (mod 4), 0 otherwise. %F A005084 a(n) = A005064(n) - A005080(n) - 8*A059841(n). - _Antti Karttunen_, Jul 11 2017 %t A005084 Array[DivisorSum[#, #^3 &, And[PrimeQ@ #, Mod[#, 4] == 3] &] &, 71] (* _Michael De Vlieger_, Jul 11 2017 *) %t A005084 f[p_, e_] := If[Mod[p, 4] == 3, p^3, 0]; a[n_] := Plus @@ f @@@ FactorInteger[n]; a[1] = 0; Array[a, 100] (* _Amiram Eldar_, Jun 21 2022 *) %o A005084 (Scheme) (define (A005084 n) (if (= 1 n) 0 (+ (if (= 3 (modulo (A020639 n) 4)) (A000578 (A020639 n)) 0) (A005084 (A028234 n))))) ;; _Antti Karttunen_, Jul 11 2017 %o A005084 (PARI) a(n) = my(f=factor(n)); sum(k=1, #f~, if (((p=f[k,1])%4) == 3, p^3)); \\ _Michel Marcus_, Jul 11 2017 %Y A005084 Cf. A000578, A005064, A005080, A005082, A005083, A005085, A059841. %K A005084 nonn %O A005084 1,3 %A A005084 _N. J. A. Sloane_ %E A005084 More terms from _Antti Karttunen_, Jul 11 2017