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A086015
Number of 7's in decimal expansion of n^2.
11
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 2, 0, 0, 0, 0, 0, 1, 0, 1, 1, 1, 1, 2, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
OFFSET
0,77
LINKS
MATHEMATICA
DigitCount[(Range[0, 100])^2, 10, 7] (* G. C. Greubel, Dec 13 2016 *)
PROG
(PARI) A086015(n)=#select(d->d==7, digits(n^2)) \\ M. F. Hasler, Feb 21 2016
CROSSREFS
Cf. 0's A086008, 1's A086009, 2's A086010, 3's A086011, 4's A086012, 5's A086013, 6's A086014, 8's A086016, 9's A086017.
Cf. A269247 for the n^3 analog.
Sequence in context: A122180 A363742 A033772 * A249856 A086012 A248394
KEYWORD
base,nonn
AUTHOR
Jason Earls, Jul 07 2003
STATUS
approved