A079009 Least k such that the 2^n successive values of phi(k+j) (j=0..2^n-1) are all distinct.

1, 2, 11, 37, 149, 1359, 14130, 175327, 1218073, 108387730, 14305141265

Offset

0,2

Links

Table of n, a(n) for n=0..10.

Formula

a(n) = A079008(2^n).

Example

For n = 7: a(7) = 175327 because phi(175327+j), for j=0..127 are all distinct: {175326, 87648, ..., 175452, 85320}.

Prog

(PARI) isdist(v) = forstep(i = #v, 1, -1, forstep(j = i - 1, 1, -1, if(v[i] == v[j], return(j)))); 0;
a(n) = {my(m = 2^n, phis = vector(m, i, eulerphi(i)), k = m, ind = isdist(phis)); while(ind != 0, phis = concat(vecextract(phis, Str("^1.."ind)), vector(ind, i, eulerphi(k+i))); k += ind; ind = isdist(phis)); k - m + 1; } \\ Amiram Eldar, Aug 27 2024

Crossrefs

Cf. A000010, A079008, A079007, A048892.

Sequence in context: A220888 A289616 A038607 * A097651 A320540 A059673

Adjacent sequences: A079006 A079007 A079008 * A079010 A079011 A079012

Keyword

nonn,more

Author

Labos Elemer, Jan 10 2003

Extensions

a(8)-a(9) from Donovan Johnson, Oct 27 2008

a(10) from Donovan Johnson, Nov 13 2010

Status

approved