A368812 - OEIS

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A368812

Numbers m such that Sum_{k=0..m-1} exp(2*Pi*i*k^5/m) != 0.

1, 4, 8, 9, 11, 16, 25, 27, 31, 32, 36, 41, 44, 49, 61, 71, 72, 81, 88, 99, 100, 101, 108, 121, 124, 125, 128, 131, 144, 151, 164, 169, 176, 181, 191, 196, 200, 211, 216, 225, 241, 243, 244, 248, 251, 256, 271, 275, 279, 281, 284, 288, 289, 297, 311, 324, 328, 331, 341, 343, 352, 361, 369, 392, 396, 400, 401, 404

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

Connect lines between the consecutive partial sums of Sum_{k=0..m-1} exp(2*Pi*i*k^5/m) != 0; this sequence gives values of m for which the resulting graph is "infinite."

A368959 is the intersection of all such sequences over exp(2*Pi*i*k^s/m), where s >= 2. Especially, all terms from A368959 are also here. - Vaclav Kotesovec, Jan 10 2024

LINKS

Table of n, a(n) for n=1..68.

EXAMPLE

4 is a term because Sum_{k=0..3} exp(2*Pi*i*k^5/4) = 2 != 0.

11 is a term because Sum_{k=0..10} exp(2*Pi*i*k^5/11) = 1 + 10*cos(2*Pi/11) != 0.

12 is not a term because Sum_{k=0..11} exp(2*Pi*i*k^5/12) = 0.

CROSSREFS

Cf. A001074, A042965 (Sum_{k=0..m-1} exp(2*Pi*i*k^(2n)/m) != 0 for all n>0).

Cf. A368959.

Sequence in context: A228653 A158758 A317253 * A229004 A306976 A266142

Adjacent sequences: A368809 A368810 A368811 * A368813 A368814 A368815

KEYWORD

easy,nonn

AUTHOR

Kevin Ge, Jan 06 2024

STATUS

approved