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 A014852 Numbers n such that n divides s(n), where s(1)=1, s(k)=5*s(k-1)+k. 0

%I

%S 1,5,55,355,605,3905,6655,25205,42955,73205,201995,277255,472505

%N Numbers n such that n divides s(n), where s(1)=1, s(k)=5*s(k-1)+k.

%C The sequence so far (for n > 1) is the smallest terms of the values of (5 * 11^i * 71^j) for i,j >= 0. Is there another term (prime?) in the product or can it be proved that all entries have this form?

%o (PARI) lista(nn) = {nb = 1000; for (n=1, nn, v = vector(nb, i, (5^(i+(n-1)*nb+1)-4*(i+(n-1)*nb)-5)/(16*(i+(n-1)*nb))); w = select(n->(type(n) == "t_INT"), v, 1); for (k=1, #w, print1(w[k]+(n-1)*nb, ", ")); kill(v););} \\ _Michel Marcus_, May 31 2014

%Y s(n) = A014827(n).

%K nonn

%O 1,2

%A _N. J. A. Sloane_, _Olivier Gérard_

%E Comment and more terms from Larry Reeves (larryr(AT)acm.org), Mar 24 2000

%E a(10)-a(13) from _Michel Marcus_, May 31 2014

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Last modified February 25 05:15 EST 2020. Contains 332217 sequences. (Running on oeis4.)