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A086290 Minimal exponent in prime factorization of 7-smooth numbers. 4
0, 1, 1, 2, 1, 1, 1, 3, 2, 1, 1, 1, 1, 4, 1, 1, 1, 1, 2, 3, 1, 1, 5, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 6, 1, 2, 1, 1, 4, 1, 1, 1, 1, 2, 1, 2, 1, 1, 3, 1, 7, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 3, 1, 2, 1, 5, 1, 1, 1, 8, 1, 1, 2, 1, 1, 1, 1, 2, 1, 3, 1, 1, 1, 1, 1, 2, 2, 1, 1, 3, 2, 1, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = A051904(A002473(n)).

a(n) <= A086291(n) <= A086289(n).

MATHEMATICA

minExp[1] = 0; minExp[n_] := Min @@ Last /@ FactorInteger[n]; minExp/@Select[Range[500], Max[Transpose[FactorInteger[#]][[1]]] <= 7 &] (* Amiram Eldar, Jan 06 2020 *)

CROSSREFS

Cf. A002473, A051904, A086289, A086291.

Sequence in context: A077481 A278113 A242012 * A136568 A152157 A039961

Adjacent sequences:  A086287 A086288 A086289 * A086291 A086292 A086293

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Jul 15 2003

STATUS

approved

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Last modified August 12 23:19 EDT 2020. Contains 336440 sequences. (Running on oeis4.)