A329899 If A181815(n) is odd, a(n) = A064989(A025487(n)), otherwise a(n) = A025487(n)/2.

1, 1, 2, 2, 4, 6, 8, 12, 6, 16, 4, 24, 30, 32, 36, 48, 60, 64, 72, 12, 96, 30, 8, 120, 128, 144, 180, 192, 210, 216, 240, 256, 288, 360, 384, 420, 432, 36, 480, 512, 24, 576, 60, 16, 720, 768, 840, 864, 900, 960, 1024, 1080, 1152, 210, 1260, 1296, 1440, 1536, 1680, 1728, 1800, 1920, 2048, 2160, 2304, 2310, 2520, 2592, 72

Offset: 1

Author

Antti Karttunen, Dec 24 2019

Keywords

• nonn

Comments

If 2-adic and 3-adic valuations of A025487(n) are equal, then a(n) = A064989(A025487(n)), otherwise a(n) = A025487(n)/2.

Only terms of A025487 occur, and each one of them occurs exactly twice.

Links

• Antti Karttunen, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A025487, A064989, A181815, A329897, A329898, A329904.

Programs

PARI

A181815(n) = A329900(A025487(n));
A064989(n) = {my(f); f = factor(n); if((n>1 && f[1,1]==2), f[1,2] = 0); for (i=1, #f~, f[i,1] = precprime(f[i,1]-1)); factorback(f)};
A329899(n) = if(A181815(n)%2,A064989(A025487(n)),A025487(n)/2);

Formula

If A181815(n) is odd, a(n) = A064989(A025487(n)), otherwise a(n) = A025487(n)/2.

a(n) = A025487(A329904(n)).