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A355940
a(n) = 1 if A003973(n) is a multiple of A000203(n), otherwise 0.
3
1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 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, 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
1
FORMULA
a(n) = [A355934(n) == 1], where [ ] is the Iverson bracket.
MATHEMATICA
f[p_, e_] := ((q = NextPrime[p])^(e + 1) - 1)/(q - 1); a[1] = 1; a[n_] := If[Divisible[Times @@ f @@@ FactorInteger[n], DivisorSigma[1, n]], 1, 0]; Array[a, 100] (* Amiram Eldar, Jul 22 2022 *)
PROG
(PARI)
A003973(n) = { my(f = factor(n)); for(i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); sigma(factorback(f)); };
A355940(n) = !(A003973(n)%sigma(n));
CROSSREFS
Characteristic function of A355941.
Sequence in context: A358750 A205809 A353370 * A348033 A327153 A374197
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jul 22 2022
STATUS
approved