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A061482
a(1) = 1, a(2) = 2, a(n) = sum of products of previous terms taking n-2 at a time.
2
1, 2, 3, 11, 127, 16195, 262286407, 68794159432716139, 4732636372053966959311918076028751, 22397847030088134373054567592093233271179679420451463713205492138771
OFFSET
1,2
COMMENTS
The next term (a(11)) has 135 digits. [From Harvey P. Dale, Feb 29 2012]
EXAMPLE
a(3) = a(1) + a(2) = 3, a(4) = a(1)a(2) + a(2)a(3) + a(3)a(1) = 11, a(5) = 1*2*3 + 1*2*11 + 1*3*11 + 2*3*11 = 127.
CROSSREFS
Cf. A061902 (lengths of terms).
Sequence in context: A050721 A058114 A042337 * A177854 A273598 A135161
KEYWORD
nonn,easy
AUTHOR
Amarnath Murthy, May 05 2001
EXTENSIONS
More terms from Asher Auel, May 05 2001. The 11th term has 135 digits.
STATUS
approved