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A083566 a(1) = 1; for n>1, a(n) = smallest odd number > a(n-1) such that a(1)*...*a(n) + 2 is a prime. 6
1, 3, 5, 7, 9, 15, 19, 25, 27, 53, 57, 65, 71, 87, 101, 151, 195, 247, 253, 255, 277, 289, 291, 301, 321, 355, 361, 443, 455, 461, 491, 531, 533, 541, 599, 603, 619, 635, 647, 667, 805, 817, 871, 1003, 1011, 1179, 1205, 1223, 1327, 1357, 1531, 1551, 1603, 1619 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
MATHEMATICA
a[1] = 1; a[n_] := a[n] = Block[{k = a[n - 1] + 2}, While[ !PrimeQ[k*Times @@ Table[a[i], {i, 1, n - 1}] + 2], k += 2]; k]; Table[ a[n], {n, 1, 54}]
nxt[{pr_, a_}]:=Module[{k=a+2}, While[!PrimeQ[pr k+2], k=k+2]; {pr k, k}]; NestList[nxt, {1, 1}, 60][[;; , 2]] (* Harvey P. Dale, Jul 10 2023 *)
CROSSREFS
Sequence in context: A340559 A073674 A084722 * A109790 A290426 A211137
KEYWORD
nonn
AUTHOR
Amarnath Murthy and Meenakshi Srikanth (menakan_s(AT)yahoo.com), Jun 13 2003
EXTENSIONS
Edited and extended by Robert G. Wilson v, Jun 17 2003
Edited by N. J. A. Sloane, Nov 01 2008 at the suggestion of R. J. Mathar
STATUS
approved

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Last modified March 28 09:04 EDT 2024. Contains 371240 sequences. (Running on oeis4.)