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A283676 a(0)=0, then a(n) = smallest odd k > a(n-1) such that 6*k^prime(n)-1 is prime. 1
0, 1, 9, 15, 47, 89, 357, 537, 697, 1037, 1257, 1643, 1723, 1995, 2333, 2357, 2863, 3395, 3593, 4795, 5187, 5349, 5469, 5759, 5859, 6339, 6573, 8097, 8653, 8683, 8773, 8827, 8947, 10213, 10609, 10959, 11407, 12325, 13365, 14109, 15549, 18589, 18639, 19343 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Pierre CAMI, Table of n, a(n) for n = 0..225

EXAMPLE

6*1^prime(1)-1 = 5 prime so a(1)=1, prime (2)=3, 6*3^3-1 = 161 composite, 6*5^3-1 = 749 composite, 6*7^3-1 = 2057 composite, 6*9^3-1 = 4373 prime so a(2) = 9.

MATHEMATICA

a[0] = 0; a[n_] := a[n] = Module[{k = Boole[OddQ@ #] + # + 1 &@ a[n - 1]}, While[! PrimeQ[6*k^Prime[n] - 1], k += 2]; k]; Table[a@ n, {n, 0, 43}] (* Michael De Vlieger, Mar 15 2017 *)

PROG

(PARI) foddk(n, k) = {while (! isprime(6*k^prime(n)-1), k+=2); k; }

lista(nn) = {k = 1; for (n=1, nn, k = foddk(n, k); print1(k, ", "); k += 2; ); } \\ Michel Marcus, Mar 18 2017

CROSSREFS

Sequence in context: A020270 A020272 A020317 * A305219 A039314 A146584

Adjacent sequences:  A283673 A283674 A283675 * A283677 A283678 A283679

KEYWORD

nonn

AUTHOR

Pierre CAMI, Mar 14 2017

STATUS

approved

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Last modified September 16 10:36 EDT 2019. Contains 327094 sequences. (Running on oeis4.)