A078327 Numbers k such that A078142(k) = A006530(k).

2, 4, 6, 8, 12, 15, 16, 18, 24, 32, 36, 45, 48, 54, 64, 72, 75, 96, 105, 108, 110, 128, 135, 144, 162, 192, 216, 220, 225, 256, 288, 315, 324, 375, 384, 385, 405, 432, 440, 486, 512, 525, 550, 576, 648, 675, 735, 768, 864, 880, 935, 945, 972, 1024, 1100, 1125

Offset: 1

Author

Jason Earls, Nov 24 2002

Keywords

• nonn

Comments

Numbers k such that the sum of the differences of the distinct prime factors p of k and the next square larger than p is equal to the largest prime factor of k.

Are there any other consecutive terms in this sequence other than 15,16 and 384,385?

Links

• Jinyuan Wang, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A006530, A078142, A078328, A145445.

Programs

PARI

is(k) = {if(k<2, return(0)); my(f=factor(k)[, 1]); sum(i=1, #f, (sqrtint(f[i])+1)^2-f[i]) == vecmax(f); } \\ Jinyuan Wang, Apr 17 2020

Extensions

Offset changed to 1 by Jinyuan Wang, Apr 17 2020