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 A025666 Exponent of 7 (value of j) in n-th number of form 4^i*7^j. 1
 0, 0, 1, 0, 1, 2, 0, 1, 2, 0, 3, 1, 2, 0, 3, 1, 4, 2, 0, 3, 1, 4, 2, 0, 5, 3, 1, 4, 2, 0, 5, 3, 1, 6, 4, 2, 0, 5, 3, 1, 6, 4, 2, 7, 0, 5, 3, 1, 6, 4, 2, 7, 0, 5, 3, 8, 1, 6, 4, 2, 7, 0, 5, 3, 8, 1, 6, 4, 9, 2, 7, 0, 5, 3, 8, 1, 6, 4, 9, 2, 7, 0, 5, 10, 3, 8, 1, 6, 4, 9, 2, 7, 0, 5, 10, 3, 8, 1, 6, 11, 4, 9, 2, 7, 0, 5 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,6 LINKS Robert Israel, Table of n, a(n) for n = 1..10000 FORMULA 4^A025648(n)*7^a(n) = A025619(n). - Robert Israel, Aug 11 2019 MAPLE N:= 10^10: # to consider all terms with 4^i*7^j<=N S:= {seq(seq(4^i*7^j, j=0..floor(log[7](N/4^i))), i=0..floor(log[4](N)))}: map(padic:-ordp, sort(convert(S, list)), 7); # Robert Israel, Aug 11 2019 CROSSREFS Cf. A025619, A025648. Sequence in context: A173863 A022337 A025687 * A025679 A071491 A156537 Adjacent sequences:  A025663 A025664 A025665 * A025667 A025668 A025669 KEYWORD nonn AUTHOR STATUS approved

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Last modified September 22 20:09 EDT 2020. Contains 337291 sequences. (Running on oeis4.)