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

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A051256 Numbers formed from binomial coefficients (mod 2) interpreted as digits in factorial base. 3
1, 3, 7, 33, 121, 843, 5167, 46233, 362881, 3991683, 40279687, 522910113, 6227383801, 93409304523, 1313941673647, 22324392524313, 355687428096001, 6758061133824003, 122000787836928007, 2561305169719296033 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
LINKS
FORMULA
a(n) = Sum_{k=0..n} (k+1)!(C(n, k) mod 2).
EXAMPLE
a(5) = 1! + 2! + 5! + 6! = 843 (only the first, second, fifth and sixth terms are odd in row 5 of Pascal's Triangle).
MAPLE
A051256(n) := proc(n) local i; RETURN(add(((binomial(n, i) mod 2)*((i+1)!)), i=0..n)); end;
MATHEMATICA
Table[Sum[(k+1)!Mod[Binomial[n, k], 2], {k, 0, n}], {n, 0, 20}] (* Harvey P. Dale, Feb 14 2013 *)
PROG
(Python)
from math import factorial
def A051256(n):
return sum(0 if ~n & k else factorial(k+1) for k in range(n+1)) # Chai Wah Wu, Feb 08 2016
CROSSREFS
Sequence in context: A238314 A120566 A057480 * A057795 A054935 A208989
KEYWORD
nonn,nice,base
AUTHOR
Antti Karttunen, Oct 24 1999
STATUS
approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 29 04:23 EDT 2024. Contains 371264 sequences. (Running on oeis4.)