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A063620
Smallest k such that 8^k has exactly n 4's in its decimal representation.
0
1, 2, 6, 14, 26, 35, 39, 37, 58, 46, 66, 103, 73, 93, 126, 124, 88, 107, 105, 173, 150, 146, 214, 194, 193, 168, 170, 229, 232, 210, 275, 248, 313, 332, 276, 300, 303, 317, 263, 314, 306, 398, 376, 422, 416, 444, 421, 394, 410, 449, 453
OFFSET
0,2
MATHEMATICA
a = {}; Do[k = 1; While[ Count[ IntegerDigits[8^k], 4] != n, k++ ]; a = Append[a, k], {n, 0, 50} ]; a
Module[{nn=500, tbl}, tbl=Table[{k, DigitCount[8^k, 10, 4]}, {k, nn}]; Table[SelectFirst[tbl, #[[2]] == n&], {n, 0, 50}]][[;; , 1]] (* Harvey P. Dale, Feb 25 2024 *)
CROSSREFS
Sequence in context: A176752 A140759 A102486 * A162716 A138318 A212964
KEYWORD
base,nonn
AUTHOR
Robert G. Wilson v, Aug 10 2001
EXTENSIONS
Name corrected by Jon E. Schoenfield, Jun 26 2018
STATUS
approved