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A165420
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a(1) = 1, a(2) = 2, a(n) = product of the previous terms for n >= 3.
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5
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1, 2, 2, 4, 16, 256, 65536, 4294967296, 18446744073709551616, 340282366920938463463374607431768211456, 115792089237316195423570985008687907853269984665640564039457584007913129639936
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OFFSET
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1,2
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COMMENTS
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Same as A001146 with 1 and 2 added in front. - Stanislav Sykora, Oct 05 2014
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LINKS
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G. C. Greubel, Table of n, a(n) for n = 1..14
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FORMULA
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a(1) = 1, a(2) = 2, a(n) = Product_{i=1..n-1} a(i), n >= 3.
a(1) = 1, a(2) = 2, a(n) = A000079(2^(n-3)) = A001146(n-3) = 2^(2^(n-3)), n >= 3.
a(1) = 1, a(2) = 2, a(3) = 2, a(n) = (a(n-1))^2, n >= 4.
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MATHEMATICA
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a[1]:= 1; a[2]:= 2; a[n_]:= Product[a[j], {j, 1, n-1}]; Table[a[n], {n, 1, 12}] (* G. C. Greubel, Oct 19 2018 *)
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PROG
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(PARI) {a(n) = if(n==1, 1, if(n==2, 2, prod(j=1, n-1, a(j))))};
for(n=1, 10, print1(a(n), ", ")) \\ G. C. Greubel, Oct 19 2018
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CROSSREFS
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Cf. A000079, A001146.
Sequence in context: A063401 A168088 A168089 * A171163 A129614 A070283
Adjacent sequences: A165417 A165418 A165419 * A165421 A165422 A165423
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KEYWORD
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nonn
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AUTHOR
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Jaroslav Krizek, Sep 17 2009
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STATUS
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approved
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