The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A007909

(Bold, blue-underlined text is an ; faded, red-underlined text is a ~~deletion~~.)
Showing entries 1-10 | older changes

Expansion of (1-x)/(1-2*x+x^2-2*x^3).
(history; published version)

#62 by Michael De Vlieger at Sat Feb 05 16:09:33 EST 2022

STATUS

proposed

#61 by Jon E. Schoenfield at Sat Feb 05 15:01:29 EST 2022

STATUS

editing

#60 by Jon E. Schoenfield at Sat Feb 05 15:01:26 EST 2022

FORMULA

a(n) = sum{k=0..floor((n-1)/3), binomial(n-k-1, 2*k)*2^k}. - Paul Barry, Sep 16 2004

a(n+1) = (2^n)*sum(((-1)^(floor(k/2)))/(2^k),k=1..n). - Yalcin Aktar, Jul 20 2008

PROG

(MAGMA) I:=[1, 1, 1]; [n le 3 select I[n] else 2*Self(n-1)-Self(n-2)+2*Self(n-3): n in [1..40]]; // Vincenzo Librandi, Jun 17 2012

STATUS

approved

#59 by Jon E. Schoenfield at Sat Feb 05 14:59:51 EST 2022

STATUS

editing

#58 by Jon E. Schoenfield at Sat Feb 05 14:59:48 EST 2022

COMMENTS

Equals INVERT transform of (1, 0, 2, 2, 2,...). - Gary W. Adamson, Apr 28 2009

STATUS

approved

#57 by Alois P. Heinz at Wed Jan 27 19:46:55 EST 2021

STATUS

proposed

#56 by Michael De Vlieger at Wed Jan 27 19:41:39 EST 2021

STATUS

editing

#55 by Michael De Vlieger at Wed Jan 27 19:41:34 EST 2021

LINKS

STATUS

approved

#54 by N. J. A. Sloane at Tue Jun 02 23:43:55 EDT 2020

STATUS

editing

#53 by N. J. A. Sloane at Tue Jun 02 23:43:53 EDT 2020

REFERENCES

STATUS

approved