login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A231609 Table whose n-th row consists of primes p such that p + 2n is the next prime, read by antidiagonals. 1
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: A269369 A305421 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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified September 25 22:55 EDT 2020. Contains 337346 sequences. (Running on oeis4.)