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A159910 Distance of prime quadruplets divided by 30, rounded towards the nearest integer. 2
0, 3, 3, 21, 22, 13, 7, 39, 7, 73, 126, 119, 88, 3, 11, 66, 29, 17, 53, 42, 101, 214, 104, 298, 252, 133, 255, 141, 76, 91, 168, 81, 45, 56, 203, 301, 43, 66, 291, 223, 92, 97, 442, 290, 437, 281, 38, 144, 549, 241, 29, 192, 11, 518, 266, 490, 122, 130, 13, 329, 85, 209 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

First differences of A007530, divided by 30 (and rounded to 0 for a(1)). The first prime quadruplet is the only one not starting at 11 (mod 30), and has no corresponding value in A014561. The "distance" can mean distance of starting points, or distance of barycenters, but also the distance in the strict sense (differing by 8 from the former), which gives the same value after rounding to the nearest integer.

All terms are of the form {0, 1, 3, 4, 6} mod 7. - Hugo Pfoertner, May 29 2020

LINKS

Hugo Pfoertner, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = (A007530(n+1)-A007530(n))/30 = A014561(n)-A014561(n-1) for n>1.

EXAMPLE

a(2) = A014561(2)-A014561(1) = 3-0, a(3) = A014561(3)-A014561(2) = 6-3, ...

PROG

(PARI) A159910( n, list=0, s=5 )={ my(o, p, q, r); until(n--<0, o=s; until( p+8==s=nextprime(s+2), p=q; q=r; r=s); list & p>o & print1((s-o)\30, ", "); ); (s-o)\30}

CROSSREFS

Cf. A007530, A014561, A047299.

Sequence in context: A112534 A006656 A205452 * A172485 A230647 A130723

Adjacent sequences: A159907 A159908 A159909 * A159911 A159912 A159913

KEYWORD

nonn

AUTHOR

M. F. Hasler, May 04 2009

STATUS

approved

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Last modified December 5 20:21 EST 2022. Contains 358588 sequences. (Running on oeis4.)