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A092404 phi(n)+phi(n+1). 4
2, 3, 4, 6, 6, 8, 10, 10, 10, 14, 14, 16, 18, 14, 16, 24, 22, 24, 26, 20, 22, 32, 30, 28, 32, 30, 30, 40, 36, 38, 46, 36, 36, 40, 36, 48, 54, 42, 40, 56, 52, 54, 62, 44, 46, 68, 62, 58, 62, 52, 56, 76, 70, 58, 64, 60, 64, 86, 74, 76 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

A054521 is the following array A read along antidiagonals:

  1,  0,  0,  0,  0,  0,...

  1,  1,  1,  1,  1,  1,...

  1,  0,  1,  0,  1,  0,...

  1,  1,  0,  1,  1,  0,...

  1,  0,  1,  0,  1,  0,...

  1,  1,  1,  1,  0,  1,...

and a(n) is apparently the hook sum sum_{k=0..n} A(n,k) + sum_{r=0..n-1} A(r,n). - R. J. Mathar, Jun 30 2013

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

MATHEMATICA

Table[(EulerPhi[n] + EulerPhi[n + 1]), {n, 60}] (* Vincenzo Librandi, Sep 27 2013 *)

Total/@Partition[EulerPhi[Range[70]], 2, 1] (* Harvey P. Dale, Dec 30 2015 *)

PROG

(PARI) for(i=1, 60, print1(", "eulerphi(i)+eulerphi(i+1)))

CROSSREFS

Cf. A000010.

Sequence in context: A239492 A034298 A308162 * A094871 A157450 A195013

Adjacent sequences:  A092401 A092402 A092403 * A092405 A092406 A092407

KEYWORD

nonn,easy

AUTHOR

Jon Perry, Mar 22 2004

STATUS

approved

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Last modified February 29 05:25 EST 2020. Contains 332353 sequences. (Running on oeis4.)