A179232 Numbers in A075728 which are not one less than some prime.

120, 186, 264, 450, 504, 552, 696, 978, 1208, 1440, 1444, 1848, 2034, 2744, 4320, 4410, 5376, 6888, 7020, 9264, 9968, 10944, 10989, 13952, 16080, 19152, 23160, 29280, 31410, 34464, 38928, 39648, 49544, 56880, 60480, 67266, 73200, 78480, 82800, 91440, 102312

Offset: 1

Author

Artur Jasinski, Jul 04 2010

Keywords

• nonn

Comments

The first 30 terms of A075728 are equal to prime(k)-1 for some k. The first term here, n = 120, satisfies |sigma(n) - 2*n| = n. - Michel Marcus, Nov 02 2013

Links

• Donovan Johnson, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A006093, A075728.

Programs

PARI

lista(nn) = {rec = -1; for (n=1, nn, d = abs(sigma(n) - 2*n); if (d > rec, if (! isprime(d+1), print1(d, ", ")); rec = d;););} \\ Michel Marcus, Nov 02 2013

Formula

A075728 \ A006093.

Extensions

More terms from R. J. Mathar, Jul 05 2010

A-number typo corrected by R. J. Mathar, Jul 16 2010