login
This site is supported by donations to The OEIS Foundation.

 

Logo

Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing.
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A274139 a(n) = 2^A000265(n) = 2^numerator(n/2^n), a sequence related to Oresme numbers. 0
2, 2, 8, 2, 32, 8, 128, 2, 512, 32, 2048, 8, 8192, 128, 32768, 2, 131072, 512, 524288, 32, 2097152, 2048, 8388608, 8, 33554432, 8192, 134217728, 128, 536870912, 32768, 2147483648, 2, 8589934592, 131072, 34359738368, 512, 137438953472, 524288, 549755813888, 32 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Differences: 0, 6, -6, 30, -24, 120, -126, 510, -480, 2016, -2040, 8184, -8064, 32640, -32766, 131070, -130560, ...

GCD of differences is 6.

LINKS

Table of n, a(n) for n=1..40.

A. F. Horadam, Oresme numbers, Fib. Quart., 12 (1974), 267-271.

FORMULA

a(n) = 2^denominator(2^n/n).

a(n) = 2^(n/2^valuation(n,2)) = 2^A007814(n).

a(n) = 2*A082392(n)^2 (conjecture).

MATHEMATICA

a[n_] := 2^(n/2^IntegerExponent[n, 2]);

Array[a, 40]

PROG

(PARI) a(n) = 2^(n/2^valuation(n, 2)); \\ Michel Marcus, Jun 12 2016

CROSSREFS

Cf. A000265, A006519, A007814, A082392.

Sequence in context: A245497 A086328 A095997 * A283995 A056189 A121860

Adjacent sequences:  A274136 A274137 A274138 * A274140 A274141 A274142

KEYWORD

nonn

AUTHOR

Jean-Fran├žois Alcover and Paul Curtz, Jun 11 2016

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 6 07:09 EST 2019. Contains 329785 sequences. (Running on oeis4.)