A334109 a(n) = A329697(A225546(n)).

0, 0, 0, 1, 0, 0, 0, 1, 2, 0, 0, 1, 0, 0, 0, 1, 0, 2, 0, 1, 0, 0, 0, 1, 4, 0, 2, 1, 0, 0, 0, 1, 0, 0, 0, 3, 0, 0, 0, 1, 0, 0, 0, 1, 2, 0, 0, 1, 8, 4, 0, 1, 0, 2, 0, 1, 0, 0, 0, 1, 0, 0, 2, 2, 0, 0, 0, 1, 0, 0, 0, 3, 0, 0, 4, 1, 0, 0, 0, 1, 2, 0, 0, 1, 0, 0, 0, 1, 0, 2, 0, 1, 0, 0, 0, 1, 0, 8, 2, 5, 0, 0, 0, 1, 0

Offset

1,9

Comments

Conjecture: Each k >= 0 occurs for the first time at A334110(k) = A019565(k)^2. Note that each k must occur first time on square n, because of the identity a(n) = a(A008833(n)). However, is there any reason to exclude squares with prime exponents > 2 from the candidates? See also comments in A334204.

Links

Antti Karttunen, Table of n, a(n) for n = 1..10200

Antti Karttunen, Data supplement: n, a(n) computed for n = 1..65537

Formula

Additive with a(prime(i)^j) = A000079(i-1) * A329697(A019565(j)), a(m*n) = a(m)+a(n) if gcd(m,n) = 1.

Alternatively, additive with a(prime(i)^(2^k)) = 2^(i-1) * A329697(prime(k+1)), a(m*n) = a(m)+a(n) if A059895(m,n) = 1. - Peter Munn, May 04 2020

a(n) = A329697(A225546(n)) = A329697(A331736(n)).

a(n) = a(A008833(n)).

For all n >= 0, a(A334110(n)) = n, a(A334860(n)) = A334204(n).

a(A331590(m,k)) = a(m) + a(k); a(A003961(n)) = 2*a(n). - Peter Munn, Apr 30 2020

Mathematica

Map[-1 + Length@ NestWhileList[# - #/FactorInteger[#][[-1, 1]] &, #, # != 2^IntegerExponent[#, 2] &] &, Array[If[# == 1, 1, Times @@ Flatten@ Map[Function[{p, e}, Map[Prime[Log2@ # + 1]^(2^(PrimePi@ p - 1)) &, DeleteCases[NumberExpand[e, 2], 0]]] @@ # &, FactorInteger[#]]] &, 105] ] (* Michael De Vlieger, May 26 2020 *)

Prog

(PARI)
A019565(n) = factorback(vecextract(primes(logint(n+!n, 2)+1), n));
A329697(n) = if(!bitand(n, n-1), 0, 1+A329697(n-(n/vecmax(factor(n)[, 1]))));
A334109(n) = { my(f=factor(n), pis=apply(primepi, f[, 1]), es=f[, 2]); sum(k=1, #f~, (2^(pis[k]-1))*A329697(A019565(es[k]))); };

Crossrefs

Cf. A001248, A005117 (positions of zeros), A334110.

Cf. A003961, A008833, A019565, A059895, A225546, A329697, A331590, A331736, A334204, A334860.

Cf. also A334107, A334108.

Sequence in context: A206499 A277885 A333842 * A373591 A374099 A109527

Adjacent sequences: A334106 A334107 A334108 * A334110 A334111 A334112

Keyword

nonn

Author

Antti Karttunen, Apr 29 2020

Status

approved