A354923 a(n) = 1 if n is either a power of prime or 2*prime, otherwise 0.

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

Offset

1

Links

Antti Karttunen, Table of n, a(n) for n = 1..100000

Index entries for characteristic functions

Formula

For n > 4, a(n) = A010055(n) + A353478(n).

Mathematica

a[n_] := If[PrimePowerQ[n] || PrimeQ[n/2], 1, 0]; a[1] = 1; Array[a, 100] (* Amiram Eldar, Jun 13 2022 *)

Prog

(PARI) A354923(n) = ((1==n)|| isprimepower(n) || (!(n%2) && isprime(n/2)));

Crossrefs

Characteristic function of A354925.

Cf. A010055, A265128, A353478.

Cf. also A354924.

Sequence in context: A344884 A228710 A103447 * A354924 A353799 A123927

Adjacent sequences: A354920 A354921 A354922 * A354924 A354925 A354926

Keyword

nonn

Author

Antti Karttunen, Jun 13 2022

Status

approved