A269245 Number of times the digit 5 appears in the decimal expansion of n^3.

0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 0, 0, 2, 1, 0, 1, 0, 0, 0, 0, 1, 0, 1, 1, 2, 1, 1, 0, 0, 0, 1, 1, 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 1, 1, 0, 2, 2, 0, 1, 1, 2, 1, 1, 1, 1, 2, 0, 0, 0, 2, 0, 1, 1, 2

Offset

0,26

Comments

The cubes corresponding to the first occurrence of 1, 2, 3, ... are listed in A036532, i.e., A036532(n)^(1/3) = A048370(n) is the index of the first occurrence of n.

Links

Table of n, a(n) for n=0..95.

Example

0^3 = 0, 1^3 = 1, 2^3 = 8 and 3^3 = 27 all have a(0) = a(1) = a(2) = a(3) = 0 digits '5'.
5^3 = 125 has a(5) = 1 digit '5'.

Mathematica

Table[DigitCount[n^3, 10, 5], {n, 0, 100}] (* Robert Price, Mar 21 2020 *)

Prog

(PARI) A269245(n)=#select(t->t==5, digits(n^3))

Crossrefs

Cf. A036532 and A036527 - A036536; A048370 and A048365 - A048374.

Analog for the other digits 0, 1, ..., 9: A269250, A269241, A269242, A269243, A269244, A269245, A269246, A269247, A269248, A269249.

Analog for squares: A086013 (digit 5), and A086008 - A086017 for digits 0 - 9.

Sequence in context: A025439 A227840 A116852 * A321886 A060154 A061007

Adjacent sequences: A269242 A269243 A269244 * A269246 A269247 A269248

Keyword

nonn,base

Author

M. F. Hasler, Feb 20 2016

Status

approved