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Revision History for A122769 (Underlined text is an addition; strikethrough text is a deletion.)

Showing entries 1-10 | older changes
A122769 Numbers k such that k^2 is of the form 3*m^2 + 2*m + 1 (A056109).
(history; published version)
#42 by Joerg Arndt at Mon Jan 01 11:50:43 EST 2024
STATUS

editing

approved

#41 by Paolo P. Lava at Mon Jan 01 11:46:41 EST 2024
FORMULA

a(n) = -(1/6)*sqrt(3)*(7 - 4*sqrt(3))^n + (1/6)*sqrt(3)*(7 + 4*sqrt(3))^n + (1/2)*(7 + 4*sqrt(3))^n + (1/2)*(7 - 4*sqrt(3))^n. - Paolo P. Lava, Aug 06 2008

STATUS

approved

editing

#40 by Joerg Arndt at Mon Jan 27 01:28:36 EST 2020
STATUS

proposed

approved

#39 by Jon E. Schoenfield at Mon Jan 27 01:17:26 EST 2020
STATUS

editing

proposed

#38 by Jon E. Schoenfield at Mon Jan 27 01:17:23 EST 2020
FORMULA

a(n) = -(1/6)*sqrt(3)*(7 - 4*sqrt(3))^n + (1/6)*sqrt(3)*(7 + 4*sqrt(3))^n + (1/2)*(7 + 4*sqrt(3))^n + (1/2)*(7 - 4*sqrt(3))^n. [_. - _Paolo P. Lava_, Aug 06 2008]

G.f.: x*(1 - 3*x)/(1 - 14*x + x^2). [_). - _Philippe Deléham_, Nov 17 2008]

STATUS

approved

editing

#37 by Susanna Cuyler at Mon Jan 07 11:16:22 EST 2019
STATUS

proposed

approved

#36 by Franck Maminirina Ramaharo at Mon Jan 07 11:01:39 EST 2019
STATUS

editing

proposed

#35 by Franck Maminirina Ramaharo at Mon Jan 07 11:01:32 EST 2019
FORMULA

E.g.f.: (1/3)*((9*cosh(4*sqrt(3)*x) - 5*sqrt(3)*sinh(4*sqrt(3)*x))*exp(7*x) - 9). - Franck Maminirina Ramaharo, Jan 07 2019

#34 by Franck Maminirina Ramaharo at Mon Jan 07 10:58:09 EST 2019
COMMENTS

The Diophantine equation A000290(x) = A000326(y) + A000326(y-1) has the solutions x = a(n) and y = (4^n+( + (1+ + sqrt(3))^(4*n- - 3)+() + (1- - sqrt(3))^(4*n- - 3))/(3*2^(2*n- - 1)). - Bruno Berselli, Mar 04 2013

FORMULA

a(n) = ((3 - b)*(7 - 4*b)^n + (3 + b)*(7 + 4*b)^n)/6, b= = sqrt(3).

a(n) = -(1/6)*sqrt(3)*(7- - 4*sqrt(3))^n+( + (1/6)*sqrt(3)*(7+ + 4*sqrt(3))^n+( + (1/2)*(7+ + 4*sqrt(3))^n+( + (1/2)*(7- - 4*sqrt(3))^n. [Paolo P. Lava, Aug 06 2008]

G.f.: x*(1- - 3*x)/(1- - 14*x+ + x^2). [Philippe Deléham, Nov 17 2008]

STATUS

proposed

editing

#33 by Jean-François Alcover at Mon Jan 07 10:22:20 EST 2019
STATUS

editing

proposed

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Last modified August 29 09:16 EDT 2024. Contains 375511 sequences. (Running on oeis4.)