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A169963 Number of (2n+1)-digit squares in carryless arithmetic mod 10. 3
5, 46, 452, 4504, 45008, 450016, 4500032, 45000064, 450000128, 4500000256, 45000000512, 450000001024, 4500000002048, 45000000004096, 450000000008192, 4500000000016384, 45000000000032768, 450000000000065536, 4500000000000131072, 45000000000000262144 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Table of n, a(n) for n=0..19.

David Applegate, Marc LeBrun and N. J. A. Sloane, Carryless Arithmetic (I): The Mod 10 Version.

Index entries for sequences related to carryless arithmetic

Index entries for linear recurrences with constant coefficients, signature (12,-20).

FORMULA

For formula see Maple code.

a(n) = 12*a(n-1)-20*a(n-2). G.f.: -(14*x-5) / ((2*x-1)*(10*x-1)). - Colin Barker, May 11 2013

MAPLE

f :- n->2^((n-1)/2) + add( 5^d*2^((n+1)/2), d=0..(n-3)/2) + 2^((n+3)/2)*5^((n-1)/2);

CROSSREFS

See A059729 for the actual squares.

Sequence in context: A096947 A042533 A309185 * A198256 A232972 A127304

Adjacent sequences:  A169960 A169961 A169962 * A169964 A169965 A169966

KEYWORD

nonn,base,easy

AUTHOR

N. J. A. Sloane, Aug 07 2010

STATUS

approved

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Last modified December 5 09:47 EST 2020. Contains 338945 sequences. (Running on oeis4.)