A329472 Partial sums of numbers that are not squarefree.

4, 12, 21, 33, 49, 67, 87, 111, 136, 163, 191, 223, 259, 299, 343, 388, 436, 485, 535, 587, 641, 697, 757, 820, 884, 952, 1024, 1099, 1175, 1255, 1336, 1420, 1508, 1598, 1690, 1786, 1884, 1983, 2083, 2187, 2295, 2407, 2523, 2640, 2760, 2881, 3005, 3130, 3256

Offset: 1

Author

Metin Sariyar, Nov 13 2019

Keywords

• nonn
• easy

Examples

			49 is a term because 4, 8, 9, 12, 16 are the first five nonsquarefree numbers and 4 + 8 + 9 + 12 + 16 = 49.
		

Links

• Metin Sariyar, Table of n, a(n) for n = 1..16000

Crossrefs

Partial sums of A013929.

Cf. A005117, A173143.

Programs

Mathematica

Accumulate[Select[Range[1000], !SquareFreeQ[#]&]]

Formula

a(n) ~ (Pi^2/(2*Pi^2 - 12)) * n^2. - Amiram Eldar, Oct 21 2020