The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A098205 A first order iteration: n-th term is obtained from (n-1)-th by adding n-th prime and then multiplying by the n-th prime; initial value is 0. 1
 0, 9, 70, 539, 6050, 78819, 1340212, 25464389, 585681476, 16984763645, 526527673956, 19481523937741, 798742481449062, 34345926702311515, 1614258555008643414, 85555703415458103751, 5047786501512028124790 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Difference between sequences generated by this recursion with iv=1[A098206] and iv=0[A098205] provides A070826, i.e. half of n-th primorial number. Analogous recursion is A019461. LINKS FORMULA a[n]=(a[n-1]+p[n])*p[n], a[0]=0. EXAMPLE a[4]=(70+p[4])*p[4]=(70+7)*7=490+49=539= MATHEMATICA f[x_] :=(f[x-1]+Prime[x])*Prime[x]; f[1]=0; Table[f[w], {w, 1, 25}] CROSSREFS Cf. A098206, A070826, A019461. Sequence in context: A110202 A110201 A045739 * A000899 A226013 A156705 Adjacent sequences:  A098202 A098203 A098204 * A098206 A098207 A098208 KEYWORD nonn AUTHOR Labos Elemer, Oct 19 2004 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified May 14 04:27 EDT 2021. Contains 343872 sequences. (Running on oeis4.)