cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A249630 Sums of the composite numbers placed between two consecutive prime numbers (A054265), sorted in increasing order.

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%I A249630 #18 Sep 25 2015 14:21:47
%S A249630 0,4,6,12,18,27,30,42,45,60,63,72,102,108,117,130,135,138,150,170,180,
%T A249630 192,198,207,228,240,243,250,270,280,282,297,312,315,320,333,348,380,
%U A249630 387,420,430,432,462,495,522,570,585,600,618,642,651,660,670,675,693
%N A249630 Sums of the composite numbers placed between two consecutive prime numbers (A054265), sorted in increasing order.
%C A249630 The first number that occurs more than once is 2592 = a(143) = a(144). - _Robert Israel_, Nov 11 2014
%H A249630 Robert Israel, <a href="/A249630/b249630.txt">Table of n, a(n) for n = 1..10000</a>
%p A249630 N:= 1000: # to get all terms <= N
%p A249630 Primes:= select(isprime,[2,seq(2*i+1,i=1..floor(N/2))]):
%p A249630 B:= [seq((Primes[i+1]+Primes[i])*(Primes[i+1]-Primes[i]-1)/2, i=1..nops(Primes)-1)]:
%p A249630 sort(select(`<=`,B,N)); # _Robert Israel_, Nov 11 2014
%t A249630 With[{nn=60},Take[Sort[Total[Range[#[[1]]+1,#[[2]]-1]]&/@Partition[ Prime[ Range[3*nn]],2,1]],nn]] (* _Harvey P. Dale_, Sep 25 2015 *)
%o A249630 (PARI) lista() = {vitp = readvec("c:/gp/bfiles/b029707.txt"); for (k=1, #vitp, v = []; for (n=1, k, vn = vitp[n]; for (j=1, vn, newv = (prime(j+1)+prime(j))*(prime(j+1)-prime(j)-1)/2; if (! vecsearch(v, newv), v = vecsort(concat(v, newv)));););/* to see intermediate results for (i=1, #v, if (v[i] <= newv, print1(v[i], ", "));); print();*/); v;} \\ _Michel Marcus_, Nov 11 2014
%Y A249630 Cf. A054265.
%K A249630 nonn
%O A249630 1,2
%A A249630 _Yves Debeuret_, Nov 02 2014
%E A249630 More terms from _Michel Marcus_, Nov 11 2014