A309055 Record values of A309036.

2, 17, 20, 43, 107, 142, 176, 1291, 1748, 3309, 5114, 9412, 13032, 53799, 62195, 258834, 515752, 590919, 1880056, 4387977, 4982469, 8725487, 10021836, 22701799, 34769113, 75672055, 3847032954, 6476460401, 8607624876, 13054048917, 40404144055, 55300901872

Offset

1,1

Links

Giovanni Resta, Table of n, a(n) for n = 1..37

Formula

a(n) = A309036(A309056(n)).

Example

a(3) = 20 is a term because A309036(25) = 20 and A309036(k) < 20 for k < 25.

Maple

S1:= 0: S2:= 0: Recv:= NULL: count:= 0:
maxv:= 0:
for n from 1 to 200000 do
  p:= ithprime(n);
  S1:= S1 + p;
  S2:= S2 + n*p;
  v:= igcd(S1, S2);
  if v > maxv then
    maxv:= v;
    count:= count+1;
    Recv:= Recv, v;
  fi
od:
Recv;

Prog

(PARI) lista(nn) = {my(k=r=s=t=0); forprime(p=2, nn, if(gcd(s+=p, t+=(k++)*p)>r, r=gcd(s, t); print1(r, ", "))); } \\ Jinyuan Wang, Apr 16 2020

Crossrefs

Cf. A309036, A309056.

Sequence in context: A042055 A075683 A340044 * A157191 A371478 A006029

Adjacent sequences: A309052 A309053 A309054 * A309056 A309057 A309058

Keyword

nonn

Author

Robert Israel, Jul 09 2019

Extensions

a(16)-a(27) from Rémy Sigrist, Jul 09 2019

a(28) from Jinyuan Wang, Apr 16 2020

Terms a(29) and beyond from Giovanni Resta, Apr 19 2020

Status

approved