A249567 a(1)=1; thereafter a(n) = smallest square m^2 such that m^2 minus (sum of all previous terms) is prime.

1, 4, 16, 64, 144, 576, 1296, 3600, 6084, 15876, 28224, 82944, 147456, 298116, 627264, 1218816, 2433600, 4928400, 9809424, 19607184, 39237696, 78535044, 158155776, 316057284, 633830976, 1265509476, 2532303684, 5062891716, 10128007044, 20260106244, 40519274436, 81043841124

Offset

1,2

Links

Robert Israel, Table of n, a(n) for n = 1..3310

Example

16 - (1+4) = 11 (prime), 64 - (1+4+16) = 43 (prime).

Maple

A[1]:= 1: S:= 1:
for n from 2 to 100 do
  m0:= ceil(sqrt(2+S));
  if m0::odd then m0:= m0+1 fi;
  for m from m0 by 2 do
    if isprime(m^2 - S) then
      A[n]:= m^2;
      S:= S + A[n];
      break
    fi
  od
od:
seq(A[i], i=1..100); # Robert Israel, Nov 14 2016

Mathematica

A249567 = {1}; n = 2; While[n < 10^5, If[n^2 - Total[A249567] > 0 && PrimeQ[n^2 - Total[A249567]], AppendTo[A249567, n^2]]; n++]; A249567 (* Ivan N. Ianakiev, Nov 03 2014 *)

Crossrefs

Sequence in context: A328850 A330687 A027676 * A348906 A177398 A343200

Adjacent sequences: A249564 A249565 A249566 * A249568 A249569 A249570

Keyword

nonn

Author

Zak Seidov, Nov 01 2014

Status

approved