A362020 Nonnegative numbers k not ending in 0 such that, in decimal representation, the subsequence of digits of k^2 occupying an odd position is equal to the digits of k.

1, 5, 6, 11, 76, 105, 501, 505, 506, 605, 756, 826, 1001, 5941, 10005, 10505, 12731, 13921, 50001, 50005, 50006, 50105, 50501, 50505, 50506, 50605, 60005, 60505, 88705, 100001, 118905, 364231, 592421, 594941, 684006, 1000005, 1000505, 1050005, 1050505, 1355941

Offset: 1

Author

Chai Wah Wu, Apr 04 2023

Keywords

• nonn
• base

Comments

Subsequence of A326418. No term starts with the digit 2.

Crossrefs

Cf. A326418.

Programs

Python

from itertools import count, islice
def A362020_gen(startvalue=0): # generator of terms >= startvalue
    return filter(lambda n:n%10 and n==int(''.join((s:=str(n**2))[len(s)&1^1::2])),count(max(startvalue,0)))
A362020_list = list(islice(A362020_gen(),50))