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A352625 A (25,-29) Somos-4 sequence. 0
1, 2, 7, 59, 1529, 83313, 7869898, 1687054711, 1123424582771, 1662315215971057, 4257998884448335457, 23385756731869683322514, 397068399296019032727466599, 15886280085653574502219650145963, 1107464108502549897934954766675333353, 157131202095317153373302215985417166354641 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
COMMENTS
Hankel transform of A188314 with first term omitted.
LINKS
FORMULA
a(n) = (25*a(n-1)*a(n-3) - 29*a(n-2)^2)/a(n-4) for all n in Z.
a(n) = (29*a(n-1)*a(n-4) - 13*a(n-2)*a(n-3))/a(n-5) for all n in Z.
a(n) = b(1-2*n) = b(2*n+2) = A188313(-1-n) for all n in Z where b(n) = A006720(n).
EXAMPLE
G.f.: 1 + 2*x + 7*x^2 + 59*x^3 + 1529*x^4 + 83313*x^5 + ...
a(2) = 7 = 2*16 - 5*5 = det([2, 5; 5, 16]).
MATHEMATICA
b[ n_] := If[OddQ[n], a[-(n-1)/2], a[n/2-1]]; a[ n_] := If[-3<=n<=1, {23, 3, 1, 1, 2}[[n+4]], 2*b[1-n]^3*b[2-n] + b[-n]^2*(b[2-n]*b[3-n] - b[1-n]*b[4-n])];
CROSSREFS
Sequence in context: A083810 A215209 A274600 * A308681 A366328 A091687
KEYWORD
nonn
AUTHOR
Michael Somos, Mar 24 2022
STATUS
approved

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Last modified April 21 09:27 EDT 2024. Contains 371851 sequences. (Running on oeis4.)