login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A046728 Let p1, p2 be first pair of consecutive primes with difference 2n; let p3, p4 be 2nd such pair; sequence gives "wadi" value p3-p1. 1
2, 6, 8, 270, 42, 12, 180, 102, 546, 750, 822, 510, 660, 300, 534, 5208, 7140, 3302, 7800, 1476, 18840, 20706, 9570, 44960, 13986, 5862, 4672, 71118, 14538, 59370, 156348, 17688, 59184, 155736, 1782, 328694, 110370, 119616, 93402, 76116 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

REFERENCES

Enoch Haga, Exploring Prime Numbers on Your PC, 2nd edition, 1998, ISBN 1-885794-16-9, Table 5, pp. 40-41.

LINKS

Table of n, a(n) for n=1..40.

EXAMPLE

First consecutive prime pair having difference 60 is p1=43331, p2=43391; next is p3=102701, p4=102761; so a(30)=102701-43331=59370.

MATHEMATICA

Flatten[Table[Differences[First /@ Take[Select[Partition[Prime[Range[60000]], 2, 1], Differences[#] == {2 n} &], 2]], {n, 40}]] (* Jayanta Basu, Jun 27 2013 *)

PROG

(PARI) a(n)=my(k, p=2, p1); forprime(q=3, , if(q-p==2*n, if(k++>1, return(p-p1), p1=p)); p=q) \\ Charles R Greathouse IV, Jun 27 2013

CROSSREFS

Cf. A038460, A038343. a(i)=b(i)-c(i) where b(i) is A046789 and c(i) is A000230.

Sequence in context: A120709 A002689 A174727 * A110984 A021792 A200705

Adjacent sequences:  A046725 A046726 A046727 * A046729 A046730 A046731

KEYWORD

nonn

AUTHOR

Enoch Haga

EXTENSIONS

More terms from Jud McCranie

a(31) inserted by Jayanta Basu, Jun 27 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 April 21 10:03 EDT 2019. Contains 322328 sequences. (Running on oeis4.)