A380484 a(n) = 1 if n is congruent to {0, 1, 2, 3, 4, 5} mod 30, otherwise 0.

1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1

Offset

0

Comments

Period 30.

a(n) = 1 if the third rightmost digit in A049345(n) is (possibly a leading) zero, otherwise 0.

a(n) = 1 if A276086(n) is not a multiple of 5, otherwise 0, where A276086 is the primorial base exp-function.

Links

Antti Karttunen, Table of n, a(n) for n = 0..60060

Index entries for characteristic functions.

Index entries for linear recurrences with constant coefficients, signature (1,0,0,0,0,-1,1,0,0,0,0,-1,1,0,0,0,0,-1,1,0,0,0,0,-1,1).

Index entries for sequences related to primorial base.

Formula

a(n) = A079998(floor(n/6)).

a(n+30) = a(n).

Mathematica

a[n_] := Boole[Mod[n, 30] < 6]; Array[a, 120, 0] (* Amiram Eldar, Feb 03 2025 *)

Prog

(PARI)
A276086(n) = { my(m=1, p=2); while(n, m *= (p^(n%p)); n = n\p; p = nextprime(1+p)); (m); };
A380484(n) = !!(A276086(n)%5);
(PARI) A380484(n) = !((n\6)%5);

Crossrefs

Characteristic function of A380485, whose complement A380486 gives the positions of 0's.

Cf. A049345, A079998, A276086.

Sequence in context: A300294 A071041 A082551 * A152614 A127507 A204441

Adjacent sequences: A380481 A380482 A380483 * A380485 A380486 A380488

Keyword

nonn,base,easy

Author

Antti Karttunen, Feb 03 2025

Status

approved