A237608 - OEIS

A237608

Number of n-digit numbers that are divisible by a square and have the same property if any number of rightmost digits is deleted.

3, 14, 61, 263, 1128, 4788, 20271, 85885, 364408, 1546394, 6563924, 27863816, 118286561

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OFFSET

1,1

COMMENTS

See A237607 for the numbers themselves and for more comments.

The ratio r(n) = a(n+1)/a(n) seems to converge to a constant value of about 4.245...

LINKS

EXAMPLE

One-digit numbers k with moebius(k)=0 are 4, 8 and 9. Hence a(1) = 3.

PROG

(PARI) See the link (use GT_DivMod0 with "IsMoebiusZero" for the "property" argument).

CROSSREFS

KEYWORD

nonn,hard,more,base

AUTHOR

EXTENSIONS

a(12)-a(13) from Lars Blomberg, Jan 02 2016

STATUS

approved