A339973 Numbers k for which A019565(2k)-1 is a multiple of A000265(phi(A019565(2k))).

0, 1, 2, 3, 4, 8, 16, 20, 32, 33, 34, 35, 38, 41, 50, 56, 64, 128, 176, 256, 259, 290, 512, 1024, 2048, 2056, 2081, 2089, 2096, 2180, 4096, 4130, 8192, 9218, 16384, 18436, 32768, 65536, 131072, 131140, 262144, 279552, 524288, 524308, 524546, 1048576, 1048736, 2097152, 4194304, 4194352, 4194420, 4196656, 4202499, 8388608

Offset

1,3

Comments

Numbers k such that A339971(k) divides A339809(2k).

Union of {0}, A000079 and the terms of (1/2)*A048675(A339880(i)), for i >= 1, sorted into ascending order.

Links

Antti Karttunen, Table of n, a(n) for n = 1..94

Prog

(PARI)
A019565(n) = { my(m=1, p=1); while(n>0, p = nextprime(1+p); if(n%2, m *= p); n >>= 1); (m); };
isA339971(n) = { my(x=A019565(2*n)); !((x-1)%A000265(eulerphi(x))); };

Crossrefs

Positions of zeros in A339898, and of ones in A339901.

Cf. A000010, A000265, A048675, A339821, A339880, A339809, A339971, A339974.

Cf. A000079 (subsequence).

Cf. also A339816, A339906.

Sequence in context: A189740 A118841 A126294 * A224912 A162724 A244750

Adjacent sequences: A339970 A339971 A339972 * A339974 A339975 A339976

Keyword

nonn

Author

Antti Karttunen, Dec 26 2020

Status

approved