A247267 Square numbers not divisible by 100 that remain square when their most-significant (or leftmost) digit is removed.

1, 4, 9, 49, 64, 81, 225, 625, 1225, 2025, 3025, 4225, 5625, 7225, 9025, 15625, 27225, 30625, 34225, 42025, 50625, 60025, 70225, 75625, 81225, 93025, 105625, 275625, 330625, 600625, 893025, 950625, 970225, 1050625, 2030625, 3330625, 4950625, 9455625, 9765625, 15405625

Offset: 1

Author

Chai Wah Wu, Nov 01 2014

Keywords

• nonn
• base

Comments

Subsequence of A225885. It is easy to see that the multiples of 100 in A225885 are earlier entries of the sequence multiplied by 100, so this sequence removes this redundancy in some sense. It appears that all entries in A225885 after the first 3 entries ends in either 25 or 00, so this sequence appears to end in 25 after the first 3 entries.

Links

• Chai Wah Wu, Table of n, a(n) for n = 1..1185

Crossrefs

Cf. A225885, A247885. A249587.

Programs

PARI

for(n=10,10^6,if(n%100,if(issquare(n)&&issquare(n%(10^(#Str(n)-1))),print1(n,", ")))) \\ Derek Orr, Nov 01 2014

Extensions

Added 1, 4, 9 to sequence to match A225885 - Chai Wah Wu, Nov 03 2014