The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A127465 Triangle read by rows: T(n,k) = k*phi(n/k) if k|n, T(n,k)=0 otherwise. 1
 1, 1, 2, 2, 0, 3, 2, 2, 0, 4, 4, 0, 0, 0, 5, 2, 4, 3, 0, 0, 6, 6, 0, 0, 0, 0, 0, 7, 4, 4, 0, 4, 0, 0, 0, 8, 6, 0, 6, 0, 0, 0, 0, 0, 9, 4, 8, 0, 0, 5, 0, 0, 0, 0, 10, 10, 0, 0, 0, 0, 0, 0, 0, 0, 0, 11, 4, 4, 6, 8, 0, 6, 0, 0, 0, 0, 0, 12 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 LINKS Robert Israel, Table of n, a(n) for n = 1..10011 (rows 1 to 141, flattened) FORMULA T(n,k) = k*A054523(n,k). EXAMPLE First few rows of the triangle are: 1; 1, 2; 2, 0, 3; 2, 2, 0, 4; 4, 0, 0, 0, 5; 2, 4, 3, 0, 0, 6; 6, 0, 0, 0, 0, 0, 7; 4, 4, 0, 4, 0, 0, 0, 8; ... MAPLE A127465 := proc(n, k)         if n mod k = 0 then                 k*numtheory[phi](n/k) ;         else                 0;         end if; end proc: seq(seq(A127465(n, m), m=1..n), n=1..12) ; # R. J. Mathar, Nov 08 2011 CROSSREFS Cf. A054523, A000010 (column k=1), A018804 (row sums). Sequence in context: A324518 A108807 A129236 * A339033 A327028 A271707 Adjacent sequences:  A127462 A127463 A127464 * A127466 A127467 A127468 KEYWORD nonn,tabl,easy AUTHOR Gary W. Adamson, Jan 15 2007 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified August 1 12:37 EDT 2021. Contains 346385 sequences. (Running on oeis4.)