A106562 Perfect squares which are not the sum of two primes.

1, 121, 289, 529, 625, 961, 1521, 1681, 2025, 2601, 2809, 3249, 3481, 4225, 4489, 5329, 6241, 6561, 6889, 7225, 7569, 8281, 9025, 9409, 9801, 10201, 11025, 11881, 12321, 12769, 13225, 15129, 15625, 16641, 17689, 18769, 19881, 20449, 21609

Offset

1,2

Links

Table of n, a(n) for n=1..39.

Formula

A106544 with 0's removed.

Example

a(2)=121 because it is the second perfect square which is impossible to obtain summing two primes.
100 is not in the sequence because 100=97+3 (sum of two primes).

Mathematica

Select[Range[150]^2, Count[IntegerPartitions[#, {2}], _?(AllTrue[#, PrimeQ]&)]==0&] (* Harvey P. Dale, Aug 14 2025 *)

Crossrefs

Cf. A106544-A106548, A106563-A106564, A106571, A106573-A106575, A106577.

Sequence in context: A211468 A023696 A038467 * A106573 A084306 A254978

Adjacent sequences: A106559 A106560 A106561 * A106563 A106564 A106565

Keyword

easy,nonn

Author

Alexandre Wajnberg, May 09 2005

Extensions

Extended by Ray Chandler, May 12 2005

Status

approved