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A082669 Let p(n) = upper member of n-th pair of twin primes; sequence gives a(n) = p(n)*(p(n)-1)/2. 1

%I #8 Aug 13 2017 20:35:01

%S 10,21,78,171,465,903,1830,2628,5253,5886,9591,11325,16290,18528,

%T 19701,26106,28920,36585,39903,48828,60726,88410,93528,106953,136503,

%U 162735,180300,191271,206403,218130,328455,338253,343206,368511,389403

%N Let p(n) = upper member of n-th pair of twin primes; sequence gives a(n) = p(n)*(p(n)-1)/2.

%C This sequence also gives C(m, m-2) for all m such that m is the greater member of the n-th twin prime pair. - Christopher Tomaszewski (cmt1288(AT)comcast.net), Oct 26 2003

%C Let p(n) = upper member of n-th pair of twin primes; sequence gives a(n) = p(n)*(p(n)-1)/2. - _Zerinvary Lajos_, Mar 08 2007

%p ZL:=[]:for p from 1 to 890 do if (isprime(p) and isprime(p+2) ) then ZL:=[op(ZL),(binomial((p+2),p))]; fi; od; print(ZL); # _Zerinvary Lajos_, Mar 08 2007

%o (PARI) tpcomb2(n) = { forprime(x=3,n, if(isprime(x-2), print1((x)*(x-1)/2" ") ) )

%K easy,nonn

%O 0,1

%A _Cino Hilliard_, May 18 2003

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Last modified August 19 13:17 EDT 2024. Contains 375302 sequences. (Running on oeis4.)