A339816 - OEIS

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A339816

Numbers k for which A339814(k) >= A339822(k).

1, 2, 4, 5, 8, 9, 12, 14, 16, 18, 21, 32, 64, 65, 68, 72, 84, 128, 129, 132, 136, 138, 141, 145, 159, 170, 192, 204, 208, 256, 258, 261, 324, 385, 448, 462, 512, 513, 515, 516, 520, 536, 576, 578, 581, 640, 705, 723, 776, 908, 912, 1024, 1036, 1040, 1049, 1160, 1172, 1280, 1352, 1537, 1600, 1609, 1666, 1732, 1795, 2048

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

Terms of (1/2)*A048675(A339817(i)), for i = 2.., sorted into ascending order.

First occurrences of terms with binary weight (A000120) w = 1..19 are at n=1, 4, 8, 23, 50, 25, 125, 136, 176, 502, 749, 1142, 791, 1882, 2913, 4327, 17979, 16991, 12441. The terms themselves are: 1, 5, 14, 141, 908, 159, 8921, 9948, 18390, 175449, 400237, 1223389, 441805, 3234271, 28743379, 53892047, 1631024969, 1331412056, 725475951.

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..19468

PROG

(PARI)

A019565(n) = { my(m=1, p=1); while(n>0, p = nextprime(1+p); if(n%2, m *= p); n >>= 1); (m); };

isA339816(n) = { my(x=A019565(2*n)); (valuation(eulerphi(x), 2)<=valuation(x-1, 2)); };

CROSSREFS

Positions of zeros and negative terms in A339815.

Cf. A000010, A000120, A007814, A019565, A048675, A339814, A339817, A339822.

Cf. A000079 (a subsequence).

Sequence in context: A189205 A137169 A348458 * A002541 A239953 A321324

Adjacent sequences: A339813 A339814 A339815 * A339817 A339818 A339819

KEYWORD

nonn

AUTHOR

Antti Karttunen, Dec 19 2020

STATUS

approved