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A249567 a(1)=1; thereafter a(n) = smallest square m^2 such that m^2 minus (sum of all previous terms) is prime. 2
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 (list; graph; refs; listen; history; text; internal format)
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 * A177398 A343200 A227312

Adjacent sequences:  A249564 A249565 A249566 * A249568 A249569 A249570

KEYWORD

nonn

AUTHOR

Zak Seidov, Nov 01 2014

STATUS

approved

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Last modified June 18 13:35 EDT 2021. Contains 345112 sequences. (Running on oeis4.)