[seqfan] Re: Two questions

[Tomasz Ordowski]

Ami,

Thank you for this data correcting my statement.

Indeed, I was wrong about such composite numbers, but not about such prime
numbers.

Odd composite numbers n such that b(n) > a(n) are 155, 215, 221, 255, 465,
527, 561, 623, 635, 645, 663, 697, 731, 755, 765, 775, 791, 935, 969, 1025,
1075, 1105, 1115, 1173, 1241, 1247, 1255, 1271, 1275, 1333, 1353, 1397,
1415, 1419, 1435, 1469, 1513, 1533, 1535, 1581, 1631, 1651, 1655, 1705,
1757, 1799, 1853, 1905, 1963, 1967, 1971, 2047, 2139, 2155, 2159, 2193,
2195, 2201, 2261, 2263, 2265, 2295, 2325, 2329, 2365, 2397, 2409, 2465,
2471, 2495, 2501, 2567, 2583, 2635, 2669, 2697, 2703, 2759, 2827, 2847,
2855, 2869, 2873, 2921, 2937, 2967, ...

These numbers do not belong to A319009, but I can't say anything more about
them.
Does anyone know how to independently characterize these numbers?

Tom

śr., 27 lis 2019 o 12:45 Ami Eldar <amiram.eldar at gmail.com> napisał(a):

> > Odd numbers n such that a(n) = b(n) are A319009.
>
> Contrary to this statement, odd numbers n such that b(n) > a(n) are primes
> A216838 and composites 155, 215, 221, 255, 465, 527, 561, 623, 635, 645,
> 663, ... Cf. A290960.
>
> Amiram
>
>
>