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A231608 Table whose n-th row consists of primes p such that p + 2n is also prime, read by antidiagonals. 3
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 June 19 00:55 EDT 2019. Contains 324217 sequences. (Running on oeis4.)