A175212 Numbers n such that A000975(n-1)/n is an integer. Also numbers n such that arithmetic mean of the first n Jacobsthal numbers is an integer.

1, 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, 199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277, 281, 283, 293

Offset

1,2

Comments

Contains the subsequence A066488 and differs therefore from A140475. [From R. J. Mathar, Aug 09 2010]

Links

R. J. Mathar, Table of n, a(n) for n = 1..9970

Example

Arithmetic mean of partial sums of Jacobsthal numbers is an integer : 0/1=0 n=1; (0+1+1+3+5)/5=2 n=5; (0+1+1+3+5+11+21)/7=6 n=7; (0+1+1+3+5+11+21+43+85+171+341)/11=62 n=11 etc.

Crossrefs

Cf. A000975, A001045

Sequence in context: A140475 A171577 A215848 * A066047 A240710 A115232

Adjacent sequences: A175209 A175210 A175211 * A175213 A175214 A175215

Keyword

easy,nonn

Author

Ctibor O. Zizka, Mar 06 2010

Extensions

Term 34 removed, sequence extended and index in definition corrected by R. J. Mathar, Mar 29 2010

Status

approved