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A074131
Group successively larger prime numbers so that the sum of the n-th group is a multiple of n. Sequence gives the group sum divided by n for the n-th group.
4
2, 4, 6, 18, 12, 13, 79, 167, 527, 437, 66, 127, 1079, 170, 422, 1550, 542, 327, 1002, 112, 1215, 236, 2006, 394, 1685, 417, 2097, 3681, 5892, 2838, 1779, 2775, 214, 1262, 5696, 679, 2377, 7926, 28463, 9505, 20618, 6653, 6754, 1585, 13266, 6173, 5587
OFFSET
1,1
FORMULA
A074128(n)/n.
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 ], {n, 1, 50} ]; a
CROSSREFS
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