0,1

Describe the previous term! (method A - initial term is 22).

Consider (future) b(n)=10*A000027(2n)+A000027(2n+1) = 12, 34, 56, 78, 100, 122, 144, 166, 188, 210 (different of A098080= 12, 34, 56, 78, 910 ) : a(n)= first differences of b(n). [From Paul Curtz (bpcrtz(AT)free.fr), Sep 10 2008]

If A=[A158325] 484*n.^2+2*n (n>0, 486, 1940, 4362,.,); Y=[A010861] 22 (22, 22, 22 ,.,); X=[A158326] 484*n+1 (n>0, 485, 969, 1453, .,), we have, for all terms, Pell's equation X^2-A*Y^2=1. Example: 485^2-486*22^2=1; 969^2-1940*22^2=1; 1453^2-4362*22^2=1. [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Mar 16 2009]

If A=[A158329] 484*n.^2-2*n (n>0, 482, 1932, 4350,.,); Y=[A010861] 22 (22, 22, 22 ,.,); X=[A158330] 484*n-1 (n>0, 483, 967, 1451, .,), we have, for all terms, Pell's equation X^2-A*Y^2=1. Example: 483^2-482*22^2=1; 967^2-1932*22^2=1; 1451^2-4350*22^2=1. [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Mar 16 2009]

Tanya Khovanova, Recursive Sequences

Cf. A005150, A005151.

Cf. A158325, A158326 [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Mar 16 2009]

Cf. A158329, A158330 [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Mar 16 2009]

Sequence in context: A022978 A023464 A126845 this_sequence A040463 A022356 A094842

Adjacent sequences: A010858 A010859 A010860 this_sequence A010862 A010863 A010864

nonn

N. J. A. Sloane (njas(AT)research.att.com).