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A026570
a(n)=T(n,n-1), T given by A026568. Also a(n) = number of integer strings s(0),...,s(n) counted by T such that s(n)=1.
0
1, 1, 4, 7, 20, 43, 111, 259, 648, 1565, 3885, 9533, 23662, 58547, 145630, 362151, 903110, 2253615, 5633359, 14094035, 35304658, 88511733, 222115782, 557819793, 1401987930, 3526066273, 8874034647, 22346581133, 56304982154
OFFSET
1,3
COMMENTS
Also a(n)=T'(n,n-1), T' given by A026584. Also a(n) = number of integer strings s(0),...,s(n) counted by T' such that s(n)=1.
FORMULA
Conjecture: (n+1)*a(n) -2*n*a(n-1) +(-3*n-1)*a(n-2) +2*(2*n-3)*a(n-3)=0. - R. J. Mathar, Jun 23 2013
CROSSREFS
Sequence in context: A296663 A066345 A355357 * A111955 A244791 A220004
KEYWORD
nonn
STATUS
approved