A013933 - OEIS

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A013933

Numbers k such that the sum of the first k nonsquarefree numbers is nonsquarefree.

1, 2, 5, 9, 15, 16, 17, 24, 25, 26, 27, 29, 31, 32, 33, 35, 37, 40, 41, 43, 44, 45, 49, 50, 51, 58, 59, 61, 64, 66, 69, 72, 76, 77, 79, 80, 81, 82, 83, 84, 85, 88, 89, 93, 94, 95, 99, 101, 102, 103, 104, 108, 109, 110, 111, 116, 117, 118, 120, 133, 134, 137, 142, 146, 147, 149

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OFFSET

1,2

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

FORMULA

A013929(a(n)) = A013934(n). - Amiram Eldar, Feb 11 2021

MATHEMATICA

nsf = Select[Range[400], !SquareFreeQ[#] &]; Position[Accumulate@nsf, _?(!SquareFreeQ[#] &)] // Flatten (* Amiram Eldar, Feb 11 2021 *)

CROSSREFS

Cf. A013929, A013934, A013935.

Sequence in context: A320996 A051892 A006599 * A101201 A184535 A033096