A073171 - OEIS

%I #10 Oct 04 2024 06:56:10

%S 4,9,16,26,38,52,69,88,111,133,159,187,217,250,287,323,362,404,448,

%T 495,542,592,648,703,760,818,882,945,1011,1081,1152,1225,1302,1377,

%U 1457,1539,1628,1712,1800,1891,1981,2077,2176,2275,2378,2484,2586,2697,2811

%N The (n^2)-th composite number.

%H Amiram Eldar, <a href="/A073171/b073171.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = A002808(A000290(n)) = A002808(n^2). - _Amiram Eldar_, Oct 04 2024

%t c[x_] := FixedPoint[x+PrimePi[ # ]+1&, x]; Table[c[j^2], {j, 1, 100}]

%o (PARI) lista(cmax) = {my(k = 0, m = 1, m2 = 1); forcomposite(c = 1, cmax, k++; if(k == m2, print1(c, ", "); m++; m2 = m^2));} \\ _Amiram Eldar_, Oct 04 2024

%Y Cf. A000290, A002808.

%K nonn,changed

%O 1,1

%A _Labos Elemer_, Jul 19 2002