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A190621
a(n) = n if n is not divisible by 4, otherwise 0.
4
0, 1, 2, 3, 0, 5, 6, 7, 0, 9, 10, 11, 0, 13, 14, 15, 0, 17, 18, 19, 0, 21, 22, 23, 0, 25, 26, 27, 0, 29, 30, 31, 0, 33, 34, 35, 0, 37, 38, 39, 0, 41, 42, 43, 0, 45, 46, 47, 0, 49, 50, 51, 0, 53, 54, 55, 0, 57, 58, 59, 0, 61, 62, 63, 0, 65, 66, 67, 0, 69, 70, 71, 0, 73, 74, 75, 0, 77, 78, 79, 0, 81, 82, 83, 0, 85, 86
OFFSET
0,3
COMMENTS
The sequence is multiplicative.
REFERENCES
J. M. Borwein, D. H. Bailey and R. Girgensohn, Experimentation in Mathematics, A K Peters, Ltd., Natick, MA, 2004. x+357 pp. See p. 195.
FORMULA
a(n) = n * A166486(n) = n * signum(n mod 4).
G.f.: (x + 2*x^2 + 3*x^3 + 3*x^5 + 2*x^6 + x^7)/(1 - 2*x^4 + x^8). - Robert Israel, Jan 13 2020
Dirichlet g.f.: (1-4^(1-s))*zeta(s-1). - R. J. Mathar, May 17 2023
MAPLE
seq(op([0, i, i+1, i+2]), i=1..100, 4); # Robert Israel, Jan 13 2020
# alternative
A190621 := proc(n)
if modp(n, 4) <> 0 then
n;
else
0;
end if;
end proc:
seq(A190621(n), n=0..40) ; # R. J. Mathar, May 17 2023
MATHEMATICA
Table[If[Divisible[n, 4], 0, n], {n, 0, 90}] (* Harvey P. Dale, Jan 04 2019 *)
PROG
(Magma) [n mod 4 ne 0 select n else 0:n in [0..86]]; // Marius A. Burtea, Jan 13 2020
CROSSREFS
Cf. A008586, A057427, A166486, A046897 (Mobius Trans.).
Sequence in context: A243059 A332845 A351079 * A325314 A322953 A376755
KEYWORD
nonn,mult,easy
AUTHOR
N. J. A. Sloane, May 14 2011
STATUS
approved