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 A069811 #23 Aug 29 2023 09:27:30 %S A069811 0,1,2,3,4,8,9,10,11,15,16,20,21,25,29,30,31,35,36,40,44,48,49,53,54, %T A069811 58,59,63,64,73,74,75,79,83,87,91,92,96,100,104,105,114,115,119,123, %U A069811 127,128,132,133,137,141,145,146,150,154,158,162,166,167,176,177,181 %N A069811 a(n) = Sum_{k=1..n} omega(k)^2. %D A069811 G. H. Hardy and E. M. Wright, An introduction to the theory of numbers, Fifth edition, Oxford University Press, Chap. XXII, p. 357. %H A069811 Ivan Neretin, <a href="/A069811/b069811.txt">Table of n, a(n) for n = 1..10000</a> %H A069811 Paul Turán, <a href="https://doi.org/10.1112/jlms/s1-9.4.274">On a theorem of Hardy and Ramanujan</a>, Journal of the London Mathematical Society, Vol. s1-9, No. 4 (1934), pp. 274-276. %F A069811 a(n) = Sum_{k=1..n} A001221(k)^2. %F A069811 a(n) = n*log(log(n))^2 + O(n*log(log(n))) (Turán, 1934). %F A069811 a(n) = Sum_{k>=1} k^2 * A346617(n,k). - _Alois P. Heinz_, Aug 19 2021 %t A069811 Accumulate@((PrimeNu@Range@62)^2) (* _Ivan Neretin_, Mar 16 2017 *) %o A069811 (PARI) a(n) = sum(k=1, n, omega(k)^2); \\ _Michel Marcus_, Mar 16 2017 %Y A069811 Equals (A074787(n)-1)/4 for n <= 29. %Y A069811 Cf. A001221, A346617. %K A069811 easy,nonn %O A069811 1,3 %A A069811 _Benoit Cloitre_, Apr 30 2002