OFFSET
1,36
COMMENTS
As A065043 is not multiplicative, neither is this sequence.
For all numbers n with an odd number of prime factors (with mult.), a(n) = 0. Proof: In the convolution formula, when n is any term of A026424, either the divisor (n/d) or d (but not both) has an odd number of prime factors. As A065043 is zero for all A026424, it is easy to show by induction that also a(n) is zero for all such numbers. Therefore, nonzero values (including any odd values, see A359765) occur only on a subset of A028260, and A359764(n) <= A065043(n).
LINKS
FORMULA
PROG
CROSSREFS
Cf. A003961, A026424, A028260, A046523, A065043, A101296, A359764 (parity of the terms), A359765 (positions of odd terms), A359766 (of even terms), A359767.
KEYWORD
sign
AUTHOR
Antti Karttunen, Jan 13 2023
STATUS
approved