login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A369151
Numbers with a record high excess of even over odd divisors; so indices of record lows in A048272.
2
1, 2, 4, 8, 16, 24, 48, 96, 144, 192, 240, 480, 720, 960, 1440, 2880, 3360, 5040, 6720, 10080, 20160, 30240, 40320, 60480, 80640, 100800, 110880, 181440, 201600, 221760, 332640, 443520, 665280, 887040, 1108800, 1330560, 1995840, 2217600, 2661120, 2882880, 4324320, 5765760, 8648640, 11531520, 14414400
OFFSET
1,2
COMMENTS
Every term is the product of primorials, i.e., this is a subsequence of A025487, i.e., no prime factor of any term has a lower exponent than the following prime has.
LINKS
FORMULA
If n > 2, a(n) = 2*A181808(n-2) = 4*A002182(n-2).
EXAMPLE
24 is a term because 24 has 6 even divisors, {2,4,6,8,12,24}, and 2 odd divisors, {1,3}, giving a difference of 4, more than that of any number less than 24.
CROSSREFS
Cf. A048272.
Sequence in context: A138278 A326078 A089827 * A222089 A182763 A272709
KEYWORD
nonn
AUTHOR
Keith F. Lynch, Jan 14 2024
STATUS
approved