A076168 Primes p such that sum of squares of even-position digits equals the sum of squares of odd-position digits of p.

11, 1487, 4871, 7841, 15413, 20231, 22453, 23201, 25423, 28657, 29867, 41351, 43597, 44453, 45377, 45553, 47513, 48017, 48479, 49537, 49801, 51473, 53891, 57413, 65287, 67421, 80491, 83591, 86297, 87041, 89797, 102023, 104089, 105389

Offset

1,1

Comments

There are 266 such primes < 10^6, the largest being 994871 -> 9^2+4^2+7^2 = 9^2+8^2+1^2 = 146.

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Example

1487 is in the sequence because 1^2+8^2 = 4^2+7^4 = 65.

Maple

filter:= proc(n) local L, i;
  L:= convert(n, base, 10);
  add(L[i]^2*(-1)^i, i=1..nops(L)) = 0 and isprime(n)
end proc:
select(filter, [seq(i, i=3..2*10^5, 2)]); # Robert Israel, Mar 18 2026

Crossrefs

Cf. A257588. Subsequence of A352535.

Sequence in context: A015027 A160264 A351597 * A053884 A027880 A222841

Adjacent sequences: A076165 A076166 A076167 * A076169 A076170 A076171

Keyword

nonn,base

Author

Zak Seidov, Nov 01 2002

Status

approved