A081447 Smallest squares such that partial sums of the sequence plus 5 are primes.

36, 576, 36, 144, 144, 36, 36, 36, 144, 36, 144, 36, 144, 144, 36, 144, 36, 36, 324, 36, 324, 144, 900, 144, 576, 324, 576, 36, 144, 324, 900, 36, 1764, 36, 36, 36, 144, 2304, 36, 2304, 324, 36, 144, 4356, 144, 900, 900, 900, 1296, 36, 36, 144, 324, 36, 144

Offset

1,1

Comments

Members are of the form (6m)^2, m integer (A081448). Proof: Since primes are 6k+1,6k+5, squares must be 6k,6k+2. The latter squares do not exist.

Links

Table of n, a(n) for n=1..55.

Prog

(PARI) t=5; for(n=2, 100, for(k=1, 10^8, if(isprime(k^2+t), print1(k^2", "); t=t+k^2; break)))

Crossrefs

Cf. A081445, A081449.

Sequence in context: A200708 A186309 A159656 * A218311 A183356 A099764

Adjacent sequences: A081444 A081445 A081446 * A081448 A081449 A081450

Keyword

nonn

Author

Ralf Stephan, Mar 21 2003

Status

approved