OFFSET
1,1
COMMENTS
The puzzle started with a(3): 8, 12, 14, 18, 20, 24, ?.
REFERENCES
Frankfurter Allgemeine Sonntagszeitung, Jul 28, 2002, "Koennen Sie folgen?", p. 56.
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
MATHEMATICA
Flatten[{#, #+4}&/@Select[Range[700], AllTrue[#+{-1, 3}, PrimeQ]&]] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Jul 22 2014 *)
PROG
(Haskell)
import Data.List (transpose)
a072541 n = a072541_list !! (n-1)
a072541_list = concat $ transpose
[map (+ 1) a023200_list, map (+ 5) a023200_list]
-- Reinhard Zumkeller, Aug 01 2014
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Aug 04 2002
STATUS
approved