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 A231608 Table whose n-th row consists of primes p such that p + 2n is also prime, read by antidiagonals. 4
 3, 3, 5, 5, 7, 11, 3, 7, 13, 17, 3, 5, 11, 19, 29, 5, 7, 11, 13, 37, 41, 3, 7, 13, 23, 17, 43, 59, 3, 5, 11, 19, 29, 23, 67, 71, 5, 7, 17, 17, 31, 53, 31, 79, 101, 3, 11, 13, 23, 19, 37, 59, 37, 97, 107, 7, 11, 13, 31, 29, 29, 43, 71, 41, 103, 137 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS T. D. Noe, Rows n = 1..100 of triangle, flattened EXAMPLE The following sequences are read by antidiagonals {3, 5, 11, 17, 29, 41, 59, 71, 101, 107,...} {3, 7, 13, 19, 37, 43, 67, 79, 97, 103,...} {5, 7, 11, 13, 17, 23, 31, 37, 41, 47,...} {3, 5, 11, 23, 29, 53, 59, 71, 89, 101,...} {3, 7, 13, 19, 31, 37, 43, 61, 73, 79,...} {5, 7, 11, 17, 19, 29, 31, 41, 47, 59,...} {3, 5, 17, 23, 29, 47, 53, 59, 83, 89,...} {3, 7, 13, 31, 37, 43, 67, 73, 97, 151,...} {5, 11, 13, 19, 23, 29, 41, 43, 53, 61,...} {3, 11, 17, 23, 41, 47, 53, 59, 83, 89,...} ... MAPLE A231608 := proc(n, k)     local j, p ;     j := 0 ;     p := 2;     while j < k do         if isprime(p+2*n ) then             j := j+1 ;         end if;         if j = k then             return p;         end if;         p := nextprime(p) ;     end do: end proc: for n from 1 to 10 do     for k from 1 to 10 do         printf("%3d ", A231608(n, k)) ;     end do;     printf("\n") ; end do: # R. J. Mathar, Nov 19 2014 MATHEMATICA nn = 10; t = Table[Select[Range[100*nn], PrimeQ[#] && PrimeQ[# + 2*n] &, nn], {n, nn}]; Table[t[[n-j+1, j]], {n, nn}, {j, n}] CROSSREFS Cf. A001359, A023200, A023201, A023202, A023203. Cf. A046133, A153417, A049488, A153418, A153419. Cf. A020483 (numbers in first column). Cf. A086505 (numbers on the diagonal). Sequence in context: A157966 A212597 A268188 * A087715 A237714 A245145 Adjacent sequences:  A231605 A231606 A231607 * A231609 A231610 A231611 KEYWORD nonn,tabl AUTHOR T. D. Noe, Nov 26 2013 STATUS approved

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Last modified September 19 20:55 EDT 2020. Contains 337182 sequences. (Running on oeis4.)