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A169669
(first digit of n) * (last digit of n) in decimal representation.
4
0, 1, 4, 9, 16, 25, 36, 49, 64, 81, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 0, 3, 6, 9, 12, 15, 18, 21, 24, 27, 0, 4, 8, 12, 16, 20, 24, 28, 32, 36, 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 0, 6, 12, 18, 24, 30, 36, 42, 48, 54, 0, 7, 14, 21, 28, 35, 42, 49, 56, 63, 0
OFFSET
0,3
COMMENTS
a(n) = A000030(n)*A010879(n);
a(n) = A115300(n) for n<=100, A115300(101) = 0;
a(n) = A111707(n) for n<=109, A111707(110) = 1;
0 <= a(n) <= 81, range = A174995;
a(10*n + n mod 10) = a(n);
a(A008592(n)) = 0;
a(n) = a(A004086(n))*A168184(n);
LINKS
PROG
(Haskell)
a169669 n = a000030 n * mod n 10
-- Reinhard Zumkeller, Apr 29 2015
(Python)
def a(n): return int(str(n)[0])*(n%10)
print([a(n) for n in range(81)]) # Michael S. Branicky, Jul 13 2022
CROSSREFS
KEYWORD
base,nonn,hear,look
AUTHOR
Reinhard Zumkeller, Apr 05 2010
STATUS
approved