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

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A106272 Diagonal sums of number triangle A106270. 1
1, -1, -1, -6, -15, -48, -147, -477, -1577, -5339, -18373, -64125, -226385, -807025, -2900825, -10501870, -38258495, -140146660, -515897195, -1907409850, -7080017615, -26373676870, -98562581255, -369433290520, -1388466728579, -5231379691972 (list; graph; refs; listen; history; internal format)
OFFSET

0,4

FORMULA

G.f.: c(x)sqrt(1-4x)/(1-x^2), c(x) the g.f. of A000108; a(n)=sum{k=0..floor(n/2), 2*0^(n-2k)-C(n-2k)}.

CROSSREFS

Sequence in context: A117961 A095122 A082637 * A056423 A056347 A122365

Adjacent sequences:  A106269 A106270 A106271 * A106273 A106274 A106275

KEYWORD

easy,sign

AUTHOR

Paul Barry (pbarry(AT)wit.ie), Apr 28 2005

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
Recent Additions | More pages | Superseeker | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .

Last modified February 15 16:28 EST 2012. Contains 205823 sequences.