A098205 - OEIS

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.

0, 9, 70, 539, 6050, 78819, 1340212, 25464389, 585681476, 16984763645, 526527673956, 19481523937741, 798742481449062, 34345926702311515, 1614258555008643414, 85555703415458103751, 5047786501512028124790

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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

Table of n, a(n) for n=1..17.

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