A070232 a(1) = 4; a(n) = smallest composite number greater than the sum of all previous terms.

4, 6, 12, 24, 48, 95, 190, 380, 760, 1520, 3040, 6080, 12160, 24320, 48640, 97280, 194560, 389120, 778240, 1556480, 3112960, 6225920, 12451840, 24903680, 49807360, 99614720, 199229440, 398458880, 796917760, 1593835520, 3187671040

Offset: 1

Author

Amarnath Murthy, May 05 2002

Keywords

• nonn

Comments

a(n) = 95*2^(n-6) for n > 5.

Links

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

Crossrefs

Cf. A070218.

Programs

Mathematica

a = {4}; Do[b = 1 + Plus @@ a; While[ PrimeQ[b], b++ ]; a = Append[a, b], {n, 2, 30}]; a
nxt[{t_,a_}]:=Module[{k=t+1},While[!CompositeQ[k],k++];{t+k,k}]; NestList[nxt,{4,4},30][[;;,2]] (* Harvey P. Dale, Sep 14 2024 *)

Extensions

Edited by Robert G. Wilson v, May 06 2002