A231609 - OEIS

A231609

Table whose n-th row consists of primes p such that p + 2n is the next prime, read by antidiagonals.

3, 7, 5, 23, 13, 11, 89, 31, 19, 17, 139, 359, 47, 37, 29, 199, 181, 389, 53, 43, 41, 113, 211, 241, 401, 61, 67, 59, 1831, 293, 467, 283, 449, 73, 79, 71, 523, 1933, 317, 509, 337, 479, 83, 97, 101, 887, 1069, 2113, 773, 619, 409, 491, 131, 103, 107

(list; table; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

The plot has an unusual gap near 10^5. Why?

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, ...}

{ 7, 13, 19, 37, 43, 67, 79, 97, 103, 109, ...}

{ 23, 31, 47, 53, 61, 73, 83, 131, 151, 157, ...}

{ 89, 359, 389, 401, 449, 479, 491, 683, 701, 719, ...}

{ 139, 181, 241, 283, 337, 409, 421, 547, 577, 631, ...}

{ 199, 211, 467, 509, 619, 661, 797, 997, 1201, 1237, ...}

{ 113, 293, 317, 773, 839, 863, 953, 1409, 1583, 1847, ...}

{1831, 1933, 2113, 2221, 2251, 2593, 2803, 3121, 3373, 3391, ...}

{ 523, 1069, 1259, 1381, 1759, 1913, 2161, 2503, 2861, 3803, ...}

{ 887, 1637, 3089, 3413, 3947, 5717, 5903, 5987, 6803, 7649, ...}

...

MATHEMATICA

nn = 10; t = Table[{}, {nn}]; complete = 0; lastP = 3; While[complete < nn, p = NextPrime[lastP]; diff = p - lastP; If[diff <= 2*nn && Length[t[[diff/2]]] < nn - diff/2 + 1, AppendTo[t[[diff/2]], lastP]; If[Length[t[[diff/2]]] == nn - diff/2 + 1, complete++]]; lastP = p]; t2 = PadRight[t, {nn, nn}, 0]; Table[t2[[n-j+1, j]], {n, nn}, {j, n}]

CROSSREFS

Cf. A001359, A029710, A031924, A031926, A031928.

Cf. A031930, A031932, A031934, A031936, A031938.

Cf. A000230 (numbers in first column).

Sequence in context: A305421 A354544 A112071 * A046561 A112927 A097406

Adjacent sequences: A231606 A231607 A231608 * A231610 A231611 A231612

KEYWORD

nonn,tabl,look

AUTHOR

T. D. Noe, Nov 26 2013

STATUS

approved