A045789 -id:A045789 - cp's OEIS frontend

A067476 Smallest n-digit square starting with 6.

64, 625, 6084, 60025, 600625, 6002500, 60000516, 600005025, 6000051600, 60000012601, 600000512409, 6000001260100, 60000004765089, 600000028030404, 6000000011750889, 60000000353550625, 600000001175088900

Offset: 2

Amarnath Murthy, Feb 09 2002

Harvey P. Dale, Table of n, a(n) for n = 2..1000

Cf. A035073 (roots), A045789, A067479 (2..9).

Ceiling[Sqrt[6*10^Range[20]]]^2 (* Harvey P. Dale, Feb 28 2025 *)

for(n=2,21,a=ceil(sqrt(6*10^(n-1)))^2; print(a))

a(n) = ceiling(sqrt(6*10^(n-1)))^2, n>1. - Rick L. Shepherd, Feb 18 2002

More terms from Rick L. Shepherd, Feb 18 2002

A333663 a(1) = 1, then a(n) is the smallest square not occurring earlier and starting with the last nonzero digit of a(n-1).

Original entry on oeis.org

1, 16, 64, 4, 49, 9, 900, 961, 100, 121, 144, 400, 441, 169, 9025, 529, 9216, 625, 576, 676, 6084, 484, 4096, 6241, 196, 6400, 4225, 5041, 1024, 4356, 6561, 1089, 9409, 9604, 4489, 9801, 1156, 6724, 4624, 4761, 1225, 5184, 4900, 90000, 90601, 1296, 6889, 91204

Offset: 1

Bernard Schott, Sep 03 2020

Every term begins with 1, 4, 5, 6 or 9.

			The smallest square not yet in the data that begins with 1 is 16, hence a(2) = 16.

David A. Corneth, Table of n, a(n) for n = 1..10000

Cf. A155985 (variant).

Subsequences of squares with initial digit k: A045784 (k=1), A045787 (k=4), A045788 (k=5), A045789 (k=6), A045793 (k=9).

Nest[Block[{a = #, k = 1, d = Mod[#[[-1]]/10^IntegerExponent[#[[-1]] ], 10]}, While[Nand[FreeQ[a, #], d == Floor[#/10^(IntegerLength[#] - 1)] ] &[k^2], k++]; Append[a, k^2]] &, {1}, 47] (* Michael De Vlieger, Sep 11 2020 *)

nxt(va, d) = {my(k=1); while ((digits(k^2)[1]!=d) || #select(x->(x==k^2), va), k++); k^2;}
lista(nn) = {my(va = vector(nn)); va[1] = 1; for (n=2, nn, va[n] = nxt(va, digits(fromdigits(Vecrev(digits(va[n-1]))))[1]);); va;} \\ Michel Marcus, Sep 04 2020

More terms from Michel Marcus, Sep 04 2020

cp's OEIS Frontend

A067476 Smallest n-digit square starting with 6.

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