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A245366 a(n) = 1 + a(n-1) * (a(n-2) - 1) * (a(n-3) - 1) with a(0) = 1, a(1) = 2, a(2) = 3, a(3) = 4. 2
1, 2, 3, 4, 9, 55, 1321, 570673, 40677571441, 30641887385179424641, 711307017047678652146384291462042881, 886599784992546696966754646294076268713472764725575212247451289601 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
COMMENTS
Each term is relatively prime to all others except for the pairs (2,4) and (3,9).
LINKS
FORMULA
a(n) = A245384(n) + 1 for n>0.
MATHEMATICA
a[ n_] := If[ n < 4, Max[1, n+1], a[n] = 1 + a[n-1] (a[n-2] - 1) (a[n-3] - 1)];
PROG
(PARI) {a(n) = if( n<4, max(1, n+1), 1 + a(n-1) * (a(n-2) - 1) * (a(n-3) - 1))};
(Magma) I:=[2, 3, 4]; [n le 3 select I[n] else 1 + Self(n-1)*(Self(n-2) - 1)*(Self(n-3) - 1): n in [1..30]]; // G. C. Greubel, Aug 05 2018
CROSSREFS
Cf. A245384.
Sequence in context: A186928 A076018 A076017 * A135112 A286709 A082865
KEYWORD
nonn
AUTHOR
Michael Somos, Aug 21 2014
EXTENSIONS
Added a(0)=1 & changed offset - N. J. A. Sloane, Jun 16 2021
STATUS
approved

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Last modified March 29 09:32 EDT 2024. Contains 371268 sequences. (Running on oeis4.)