A076246 -id:A076246 - cp's OEIS frontend

A076245 Positions of records in A051547.

1, 3, 5, 7, 11, 15, 17, 19, 23, 29, 47, 51, 53, 59, 81, 83, 85, 101, 103, 107, 149, 163, 167, 173, 179, 191, 197, 227, 251, 255, 257, 263, 269, 283, 293, 311, 317, 347, 359, 367, 383, 389, 467, 479, 487, 503, 509, 557, 563, 569, 587, 607, 619, 643, 653, 677

Offset: 1

Labos Elemer, Oct 08 2002

nonn

Observe that both primes and composites (including 15, 51, 81, 85, and 255) occur.

In totients of consecutive terms some prime-factor appears at higher power than in preceding ones: see A076246 and A051451.

Michael De Vlieger, Table of n, a(n) for n = 1..13256 (First 1924 terms from _Vincenzo Librandi_; a(n) <= 10^6.)

Cf. A003418, A051451, A051547, A076244.

With[{s = FoldList[LCM @@ {#1, EulerPhi@ #2} &, Range[700]]}, Map[FirstPosition[s, #][[1]] &, Union@ FoldList[Max, s]]] (* Michael De Vlieger, Dec 09 2018 *)

lista(nn) = {least = 1; print1(1, ", "); for (n=2, nn, nleast = lcm(least, eulerphi(n)); if (nleast > least, print1(n, ", ")); least = nleast;);} \\ Michel Marcus, Jul 30 2017

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A076245 Positions of records in A051547.

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