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A115300
Greatest digit of n * least digit of n.
5
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, 8
OFFSET
1,2
COMMENTS
a(101) = 0 and A111707(101) = 1, but all previous terms match.
a(n) = A169669(n) for n <= 100.
LINKS
FORMULA
a(n) = A054054(n)*A054055(n). - Reinhard Zumkeller, Apr 29 2015
EXAMPLE
a(3) = 3 * 3 = 9, a(232) = 3 * 2 = 6, a(1889009898) = 9 * 0 = 0.
MATHEMATICA
Array[Max[#] * Min[#] &@ IntegerDigits[#] &, 81] (* James C. McMahon, Aug 18 2024 *)
PROG
(Haskell)
a115300 n = a054054 n * a054055 n -- Reinhard Zumkeller, Apr 29 2015
(Python)
def a(n): d = list(map(int, str(n))); return max(d) * min(d)
print([a(n) for n in range(1, 82)]) # Michael S. Branicky, Dec 12 2023
(PARI) a(n) = my(d=digits(n)); vecmin(d)*vecmax(d); \\ Michel Marcus, Aug 18 2024
CROSSREFS
Cf. A037904 (greatest-least), A115299 (greatest+least), A111707.
Sequence in context: A334832 A169669 A111707 * A085942 A066308 A063462
KEYWORD
base,nonn,look
AUTHOR
Rick L. Shepherd, Jan 20 2006
STATUS
approved