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A228543 a(n) is the integer-valued average gap between successive primes from prime(1) to prime(k(n)), where k(n) = A049036(n). 2
1, 3, 5, 7, 7, 9, 13, 13, 13, 15, 15, 19, 19, 19, 19, 19, 21, 21, 27, 29, 31 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(n) arises from A049036 and A049038.

LINKS

Table of n, a(n) for n=1..21.

FORMULA

a(n) = (A049038(n)-2)/(A049036(n)-1).

EXAMPLE

For n=1 a(n)=(p(k(1))-2)/(k(1)-1), where k(1)=2, p(2)=3, and a(1)=1;

For n=2 a(n)=(p(k(2))-2)/(k(2)-1), where k(2)=10, p(10)=29, and a(2)=3;

For n=3 a(n)=(p(k(3))-2)/(k(3)-1), where k(3)=68, p(68)=337, and a(3)=5;

MATHEMATICA

a = {}; Do[s = (Prime[k] - 2)/(k - 1); If[IntegerQ[s], AppendTo[a, s]], {k, 2, 1000000000}]; a

CROSSREFS

Cf. A049036, A049038.

Sequence in context: A261010 A064002 A195868 * A254764 A109535 A180496

Adjacent sequences:  A228540 A228541 A228542 * A228544 A228545 A228546

KEYWORD

nonn,more

AUTHOR

V.J. Pohjola, Aug 25 2013

STATUS

approved

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Last modified September 26 15:27 EDT 2017. Contains 292531 sequences.