A074126 Group the composite numbers so that the sum of the n-th group is a multiple of the n-th prime: (4), (6), (8, 9, 10, 12, 14, 15, 16, 18, 20, 21, 22), (24, 25), (26, 27, 28, 30, 32), (33, 34, ...), ... Sequence gives the number of terms in each group.

1, 1, 11, 2, 5, 21, 13, 18, 53, 18, 18, 9, 34, 63, 105, 5, 5, 6, 66, 259, 78, 16, 9, 103, 179, 100, 34, 21, 69, 431, 24, 3, 193, 233, 235, 138, 172, 64, 171, 161, 229, 51, 44, 598, 363, 733, 924, 362, 224, 99, 77, 54, 142, 261, 332, 5, 216, 592, 67, 72, 1140, 86, 336, 91, 43

Offset

1,3

Links

Table of n, a(n) for n=1..65.

Prog

(PARI) { n=3; for(k=1, 100, r=0; s=0; c=0; while(!s||(s%prime(k)>0), if(!isprime(n), s=s+n; c++ ; if(!r, r=n) ); n=n+1 ); print1(c", ") ) } - R. J. Mathar, Nov 10 2006

Crossrefs

Cf. A074124, A074125, A074127.

Sequence in context: A089566 A010191 A064791 * A107831 A064928 A074335

Adjacent sequences: A074123 A074124 A074125 * A074127 A074128 A074129

Keyword

nonn

Author

Amarnath Murthy, Aug 27 2002

Extensions

Corrected and extended by R. J. Mathar, Nov 10 2006

Status

approved