A072475 Sum of next n composite numbers.

4, 14, 31, 63, 112, 176, 264, 385, 529, 712, 932, 1184, 1503, 1833, 2234, 2689, 3207, 3779, 4408, 5117, 5913, 6747, 7657, 8667, 9766, 10938, 12240, 13612, 15071, 16578, 18266, 20081, 22007, 23989, 26100, 28334, 30695, 33221, 35811, 38569, 41474

Offset

1,1

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Mathematica

Composite[n_Integer] := FixedPoint[n + PrimePi[ # ] + 1 &, n + PrimePi[n] + 1]; Table[ Sum[ Composite[i], {i, n(n - 1)/2 + 1, n(n + 1)/2}], {n, 1, 42}]
With[{terms=50}, cnos=With[{c=(terms(terms+1)(terms+2))/6}, Complement[ Range[5, c], Prime[Range[PrimePi[c]]]]]; Join[{4}, Total/@Table[Take[ cnos, {n (n+1)/2, (n+1) (n+2)/2-1}], {n, terms-1}]]] (* Harvey P. Dale, Oct 10 2011 *)

Crossrefs

Cf. A072474, A007468, A006003.

Sequence in context: A317031 A140063 A051409 * A001740 A129395 A023539

Adjacent sequences: A072472 A072473 A072474 * A072476 A072477 A072478

Keyword

nonn

Author

Amarnath Murthy, Jun 20 2002

Extensions

More terms from Jim Nastos and Robert G. Wilson v, Jun 21 2002

Status

approved