A309056 Where records of A309036 occur.

1, 4, 25, 26, 43, 77, 201, 336, 881, 2144, 22305, 24113, 44349, 48748, 153884, 400161, 793873, 1195455, 5066329, 6227954, 11394871, 16233979, 18368369, 63843903, 80998288, 117335658, 246252769, 6420049930, 23198011949, 30432298548, 62709861290, 117888644809

Offset: 1

Author

Robert Israel, Jul 09 2019

Keywords

• nonn

Comments

Numbers m such that A309036(m) > A309036(k) for all k < m.

Examples

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

Links

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

Crossrefs

Cf. A309036, A309055.

Programs

Maple

S1:= 0: S2:= 0: Recn:= 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;
    Recn:= Recn, n;
  fi
od:
Recn;

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(k, ", "))); } \\ Jinyuan Wang, Apr 16 2020

Formula

A309055(n) = A309036(a(n)).

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