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 A382069 #15 Mar 14 2025 21:16:05 %S A382069 1,4,10,18,31,42,64,80,105,128,166,182,235,262,300,344,409,432,514, %T A382069 538,607,674,760,776,885,952,1026,1086,1219,1230,1396,1440,1545,1652, %U A382069 1738,1794,1999,2074,2176,2240,2461,2472,2710,2758,2871,3062,3244,3240,3493 %N A382069 Row sums of the triangular array in A199408. %F A382069 a(n) = A000217(n) + A000290(n) - A018804(n). %F A382069 a(A000040(n)) = A001248(n) + A006093(n)*A040976(n)/2. %F A382069 a(A000040(n)) = A001248(n) + A087397(n) for n > 2. %e A382069 n = 3: a(3) = 3 + 4 + 3 = 10. %e A382069 n = 4: a(4) = 4 + 4 + 6 + 4 = 18. %t A382069 f[p_, e_] := (e*(p-1)/p + 1) * p^e; a[n_] := n*(3*n+1)/2 - Times @@ f @@@ FactorInteger[n]; Array[a, 50] (* _Amiram Eldar_, Mar 14 2025 *) %Y A382069 Cf. A000040, A000217, A000290, A001248, A006093, A018804, A040976, A087397, A199408. %K A382069 nonn %O A382069 1,2 %A A382069 _Ctibor O. Zizka_, Mar 14 2025