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A098206 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 1.

%I A098206 #18 Jun 18 2021 15:52:18
%S A098206 1,12,85,644,7205,93834,1595467,30314234,697227911,20219610260,
%T A098206 626807919021,23191893005146,950867613212667,40887307368146530,
%U A098206 1921703446302889119,101850282654053126116,6009166676589134444325
%N A098206 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 1.
%H A098206 Harvey P. Dale, <a href="/A098206/b098206.txt">Table of n, a(n) for n = 1..350</a>
%F A098206 a(n) = (a(n-1)+prime(n))*prime(n), a(1)=1.
%F A098206 a(n) = product(j=2..n, prime(j)) + sum(k=2..n, prime(k)*product(j=k..n, prime(j))). - _Robert Israel_, Feb 12 2015
%e A098206 n=4: a(4)=(a(3)+7)*7=(85+7)*7=644.
%p A098206 a:= n -> mul(ithprime(j),j=2..n) + add(ithprime(k)*mul(ithprime(j),j=k..n),k=2..n):
%p A098206 seq(a(n), n=1..30); # _Robert Israel_, Feb 12 2015
%t A098206 f[x_]:=(f[x-1]+Prime[x])*Prime[x];f[1]=0;Table[f[w], {w, 1, 25}]
%t A098206 nxt[{n_,a_}]:=Module[{p=Prime[n+1]},{n+1,p(a+p)}]; NestList[nxt,{1,1},20][[All,2]] (* _Harvey P. Dale_, Jun 18 2021 *)
%Y A098206 Cf. A070826, A019461.
%K A098206 nonn
%O A098206 1,2
%A A098206 _Labos Elemer_, Oct 19 2004