A340149 - OEIS

The OEIS is supported by the many generous donors to the OEIS Foundation.

A340149

Odd part of A340147: a(n) = A000265(A247074(A003961(n))).

1, 1, 1, 3, 1, 1, 1, 9, 5, 3, 1, 3, 1, 5, 3, 27, 1, 5, 1, 9, 5, 3, 1, 9, 7, 1, 25, 15, 1, 3, 1, 81, 3, 9, 15, 15, 1, 11, 1, 27, 1, 5, 1, 9, 5, 7, 1, 27, 11, 21, 9, 3, 1, 25, 1, 45, 11, 15, 1, 9, 1, 9, 25, 243, 3, 3, 1, 27, 7, 3, 1, 45, 1, 5, 21, 33, 15, 1, 1, 81, 125, 21, 1, 15, 3, 23, 15, 27, 1, 15, 5, 21, 9, 13, 33 (list; graph; refs; listen; history; text; internal format)

	OFFSET	`1,4`
	COMMENTS	`Each term a(n) is a divisor of A340075(n), at n=85 occurs the first proper divisor.`
	LINKS	`Antti Karttunen, Table of n, a(n) for n = 1..8191` `Antti Karttunen, Data supplement: n, a(n) computed for n = 1..65537` `Index entries for sequences computed from indices in prime factorization`
	FORMULA	`a(n) = A000265(A340147(n)) = A000265(A247074(A003961(n))).`
	PROG	`(PARI)` `A000265(n) = (n>>valuation(n, 2));` `A003961(n) = { my(f = factor(n)); for(i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); };` `A247074(n) = { my(f=factor(n)); eulerphi(f)/prod(i=1, #f~, gcd(f[i, 1]-1, n-1)); }; \\ From A247074` `A340149(n) = A000265(A247074(A003961(n)));`
	CROSSREFS	`Cf. A000265, A003961, A247074, A340147, A340150 (positions of ones).` `Differs from related A340075 for the first time at n=85, where a(85) = 3, while A340075(85) = 9.` `Sequence in context: A348038 A327564 A243748 * A340075 A307847 A080214` `Adjacent sequences: A340146 A340147 A340148 * A340150 A340151 A340152`
	KEYWORD	`nonn`
	AUTHOR	`Antti Karttunen, Dec 30 2020`
	STATUS	`approved`

License Agreements, Terms of Use, Privacy Policy. .

Last modified August 18 13:06 EDT 2024. Contains 375269 sequences. (Running on oeis4.)