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A309039 Highly composite numbers (A002182) that are not highly Brazilian (A279930). 1
2, 4, 6, 12, 36, 48, 240 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Is there a proof that this sequence is infinite?

Indeed, from 1680 to 2882880, that is, during 26 successive terms (maybe more?), highly composite numbers are the same as highly Brazilian numbers. - Bernard Schott, Jul 12 2019

LINKS

Table of n, a(n) for n=1..7.

EXAMPLE

2 is a highly composite number (A002182) but is not in A279930 (where 1 is followed immediately by 24), so 2 qualifies for this sequence.

Integer 48 is highly composite with tau(48) = 10, and 48 = 66_7 = 44_11 = 33_15 = 22_33 so beta(48) = 4. We have also beta(40) = 4 with 40 = 1111_3 = 55_7 = 44_9 = 22_19 so 48 is not highly Brazilian. 48 is a term because it is highly composite but not highly Brazilian. - Bernard Schott, Jul 12 2019

CROSSREFS

Cf. A002182 (highly composites), A066044 (highly Brazilian numbers), A279930 (highly composites and highly Brazilian numbers).

Sequence in context: A220423 A308618 A283021 * A087902 A282193 A180213

Adjacent sequences:  A309036 A309037 A309038 * A309040 A309041 A309042

KEYWORD

nonn,more,hard

AUTHOR

J. Lowell, Jul 08 2019

STATUS

approved

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Last modified February 26 00:52 EST 2020. Contains 332270 sequences. (Running on oeis4.)