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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A061159 Numerators in expansion of Euler transform of b(n) = 1/2. 4
1, 1, 7, 17, 203, 455, 2723, 6001, 133107, 312011, 1613529, 3705303, 39159519, 88466147, 443939867, 1041952049, 40842931395, 93889422323, 460998957853, 1054706036923, 10194929714949, 23513104814105, 111438617932133, 255719229005751, 4864448363248503 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

Denominators of c(n) are 2^d(n), where d(n)=power of 2 in (2n)!, cf. A005187.

LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..1000

Geoffrey B. Campbell, A Zujev, Some almost partition theoretic identities, Preprint, 2016

N. J. A. Sloane, Transforms

FORMULA

Numerators of c(n), where c(n)=1/(2*n)*Sum_{k=1..n} c(n-k)*sigma(k), n>0, c(0)=1.

MAPLE

b:= proc(n) option remember; `if`(n=0, 1, add(add(

      d/2, d=numtheory[divisors](j))*b(n-j), j=1..n)/n)

    end:

a:= n-> numer(b(n)):

seq(a(n), n=0..35);  # Alois P. Heinz, Jul 28 2017

CROSSREFS

Cf. A000712, A061160, A061161.

Sequence in context: A244279 A214149 A147643 * A178694 A140122 A092240

Adjacent sequences:  A061156 A061157 A061158 * A061160 A061161 A061162

KEYWORD

easy,nonn,frac

AUTHOR

Vladeta Jovovic, Apr 17 2001

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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified August 23 15:21 EDT 2017. Contains 291004 sequences.