A204504 A204512(n)^2 = floor[A055872(n)/8]: Squares such that appending some digit in base 8 yields another square.

0, 0, 0, 1, 4, 36, 144, 1225, 4900, 41616, 166464, 1413721, 5654884, 48024900, 192099600, 1631432881, 6525731524, 55420693056, 221682772224, 1882672131025, 7530688524100, 63955431761796, 255821727047184, 2172602007770041, 8690408031080164, 73804512832419600

Offset

1,5

Comments

Base-8 analog of A202303.

Links

Table of n, a(n) for n=1..26.

Formula

a(n)=A204512(n)^2.

G.f. = x^4*(1 + 4*x + x^2 + 4*x^3)/(1 - 35*x^2 + 35*x^4 - x^6)

Prog

(PARI) b=8; for(n=1, 2e9, issquare(n^2\b) & print1((n^2\b)", "))
(PARI) a(n)=polcoeff(x^4*(1 + 4*x + x^2 + 4*x^3)/(1 - 35*x^2 + 35*x^4 - x^6+O(x^n)), n)

Crossrefs

See also A031149=sqrt(A023110) (base 10), A204502=sqrt(A204503) (base 9),

A204514=sqrt(A055872) (base 8), A204516=sqrt(A055859) (base 7),

A204518=sqrt(A055851) (base 6), A204520=sqrt(A055812) (base 5),

A004275=sqrt(A055808) (base 4), A001075=sqrt(A055793) (base 3),

A001541=sqrt(A055792) (base 2).

Sequence in context: A340661 A035287 A183354 * A083223 A102263 A103931

Adjacent sequences: A204501 A204502 A204503 * A204505 A204506 A204507

Keyword

nonn,base

Author

M. F. Hasler, Jan 15 2012

Status

approved