A030481 Squares of primes, with property that all even digits occur together and all odd digits occur together.

4, 9, 25, 49, 289, 841, 2209, 2809, 4489, 6241, 6889, 22201, 22801, 24649, 66049, 80089, 208849, 426409, 466489, 822649, 2042041, 2468041, 2866249, 2886601, 4068289, 6046681, 6086089, 6466849, 6806881, 6848689, 8082649, 8288641, 8462281, 8826841, 22648081, 26020201, 26822041, 28440889, 44262409

Offset

1,1

Comments

Since the 10's digit of any odd square is even, all digits except the last must be even. - Robert Israel, Jan 04 2024

Links

Robert Israel, Table of n, a(n) for n = 1..3000

Maple

filter:= proc(n) local L;
  convert(convert(floor(n/10), base, 10), set) mod 2 = {0}
end proc:
[4, 9, op(select(filter, [seq(ithprime(i)^2, i=3..20000)]))]; # Robert Israel, Jan 04 2024

Crossrefs

Includes (2*10^(2k) + 2*10^k + 1)^2 for k in A296444.

Sequence in context: A028866 A146981 A068373 * A160190 A226917 A032127

Adjacent sequences: A030478 A030479 A030480 * A030482 A030483 A030484

Keyword

nonn,base

Author

Patrick De Geest

Extensions

More terms from Robert Israel, Jan 04 2024

Status

approved