A257554 Numbers k such that A007954(k) divides k and k divides A007954(k)^2.

1, 2, 3, 4, 5, 6, 7, 8, 9, 36, 128, 175, 384, 735, 1296, 2916, 18432, 34992, 82944, 139968, 442368, 2333772, 4128768, 9289728, 12192768, 13226976, 13395375, 13436928, 27869184, 49787136, 376233984, 429981696, 1269789696, 2633637888, 4161798144, 16728477696, 19999187712, 41479796736, 72236924928

Offset: 1

Author

Max Alekseyev, Apr 29 2015

Keywords

• nonn
• base

Comments

There are 66 terms below 10^400 with the largest containing 46 digits.

Links

• Max Alekseyev, Table of n, a(n) for n = 1..66

Crossrefs

Intersection of A007602 and A128606.

Programs

PARI

for(n=1,10^6, d=digits(n); p=prod(i=1,#d,d[i]); if(p && n%p==0 && p^2%n==0, print1(n,", ") )) \\ Derek Orr, Apr 29 2015