A249630 Sums of the composite numbers placed between two consecutive prime numbers (A054265), sorted in increasing order.
0, 4, 6, 12, 18, 27, 30, 42, 45, 60, 63, 72, 102, 108, 117, 130, 135, 138, 150, 170, 180, 192, 198, 207, 228, 240, 243, 250, 270, 280, 282, 297, 312, 315, 320, 333, 348, 380, 387, 420, 430, 432, 462, 495, 522, 570, 585, 600, 618, 642, 651, 660, 670, 675, 693
Offset: 1
Keywords
Links
- Robert Israel, Table of n, a(n) for n = 1..10000
Crossrefs
Cf. A054265.
Programs
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Maple
N:= 1000: # to get all terms <= N Primes:= select(isprime,[2,seq(2*i+1,i=1..floor(N/2))]): B:= [seq((Primes[i+1]+Primes[i])*(Primes[i+1]-Primes[i]-1)/2, i=1..nops(Primes)-1)]: sort(select(`<=`,B,N)); # Robert Israel, Nov 11 2014
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Mathematica
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 *)
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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
Extensions
More terms from Michel Marcus, Nov 11 2014
Comments