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A065516 Differences between products of 2 primes. 48
2, 3, 1, 4, 1, 6, 1, 3, 1, 7, 1, 1, 3, 1, 7, 3, 2, 4, 2, 1, 4, 3, 4, 5, 3, 5, 3, 1, 1, 4, 2, 1, 1, 11, 5, 4, 3, 1, 2, 1, 1, 6, 4, 1, 7, 1, 1, 2, 1, 9, 3, 1, 2, 5, 3, 8, 1, 5, 2, 2, 7, 7, 1, 1, 2, 1, 3, 4, 1, 1, 2, 1, 1, 2, 5, 9, 2, 10, 2, 4, 1, 5, 3, 3, 2, 7, 4, 9, 2, 2, 4, 3, 1, 2, 1, 1, 2, 4, 5, 5, 2, 2, 3, 1, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

See A215231 and A085809 for record values and where they occur: A215231(n) = a(A085809(n)). - Reinhard Zumkeller, Mar 23 2014

LINKS

T. D. Noe, Table of n, a(n) for n=1..10000

D. A. Goldston, S. W. Graham, J. Pintz and C. Y. Yildirim, Small gaps between primes and almost primes, arXiv:math/0506067 [math.NT], 2005.

FORMULA

a(n) = A001358(n+1) - A001358(n).

EXAMPLE

a(6) = A001358(7) - A001358(6) = 21 - 15 = 6.

MATHEMATICA

Differences[Select[Range[329], PrimeOmega[#] == 2 &]] (* Arkadiusz Wesolowski, Nov 24 2011 *)

PROG

(PARI) {spg(m)=local(a, b); a=0; b=4; for(n=5, m, if(bigomega(n) == 2, a=n; print1(a-b", "); b=a; ))}

(Haskell)

a065516 n = a065516_list !! (n-1)

a065516_list = zipWith (-) (tail a001358_list) a001358_list

-- Reinhard Zumkeller, Mar 23 2014

CROSSREFS

Cf. A001358.

Cf. A239656.

Sequence in context: A205790 A235791 A035426 * A280699 A214967 A195164

Adjacent sequences:  A065513 A065514 A065515 * A065517 A065518 A065519

KEYWORD

easy,nonn

AUTHOR

Lior Manor, Nov 27 2001

EXTENSIONS

More terms from Jason Earls (zevi_35711(AT)yahoo.com), Jul 24 2003

STATUS

approved

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Last modified March 25 01:30 EDT 2017. Contains 284036 sequences.