A074128 Group successively larger prime numbers so that the sum of the n-th group is a multiple of n. Sequence gives the sum for each group.

2, 8, 18, 72, 60, 78, 553, 1336, 4743, 4370, 726, 1524, 14027, 2380, 6330, 24800, 9214, 5886, 19038, 2240, 25515, 5192, 46138, 9456, 42125, 10842, 56619, 103068, 170868, 85140, 55149, 88800, 7062, 42908, 199360, 24444, 87949, 301188, 1110057

Offset

1,1

Links

Table of n, a(n) for n=1..39.

Mathematica

NextPrime[n_] := Block[{k = n + 1}, While[ !PrimeQ[k], k++ ]; k]; a = {}; k = 1; Do[s = 0; While[k = NextPrime[k]; s = s + k; !IntegerQ[s/n], ]; a = Append[a, s], {n, 1, 40}]; a

Crossrefs

Cf. A000040, A074129, A074130, A074131.

Sequence in context: A054358 A387370 A268658 * A376114 A061226 A134827

Adjacent sequences: A074125 A074126 A074127 * A074129 A074130 A074131

Keyword

nonn

Author

Amarnath Murthy, Aug 27 2002

Extensions

(2), (3, 5), (7, 11), (13, 17, 19, 23), (29, 31), (37, 41), (43, 47, 53, 59, 61, 67, 71, 73, 79), (83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139), (149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, ..., 269), ...

Edited, corrected and extended by Robert G. Wilson v, Aug 29 2002

Status

approved