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A218532 Number of times n consecutively appears in A218461. 0
2, 3, 5, 10, 21, 44, 92, 216, 446, 1018, 2356, 5408, 12559, 29709, 70446, 169008, 407539, 988057, 2415086, 5927972 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(n) is roughly e^n*(e-1)/n. - Charles R Greathouse IV, Aug 20 2013

LINKS

Table of n, a(n) for n=1..20.

PROG

(PARI) a(nn) = my(lpn=1, lfn=1); for (i=2, nn, p = prime(i); fn = prime(p)\p; if (fn != lfn, print1(i - lpn, ", "); lfn = fn; lpn = i)) \\ Michel Marcus, Aug 16 2013

(PARI) a(n)=my(p=2, t=p, s, quot); forprime(q=2, , if(t--, next); quot=q\p; if(quot>=n, if(quot>n, return(s), s++)); t=nextprime(p+1)-p; p+=t) \\ Charles R Greathouse IV, Aug 20 2013

CROSSREFS

Cf. A218461 (floor(prime(prime(n))/prime(n))).

Sequence in context: A024494 A131708 A002991 * A022861 A001646 A103595

Adjacent sequences:  A218529 A218530 A218531 * A218533 A218534 A218535

KEYWORD

nonn

AUTHOR

Tyler Carrico, Oct 31 2012

EXTENSIONS

a(13) from Michel Marcus, Aug 16 2013

a(14)-a(20) from Charles R Greathouse IV, Aug 20 2013

STATUS

approved

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Last modified February 22 20:30 EST 2019. Contains 320404 sequences. (Running on oeis4.)