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A258434 n^2 - phi(n). 2
0, 3, 7, 14, 21, 34, 43, 60, 75, 96, 111, 140, 157, 190, 217, 248, 273, 318, 343, 392, 429, 474, 507, 568, 605, 664, 711, 772, 813, 892, 931, 1008, 1069, 1140, 1201, 1284, 1333, 1426, 1497, 1584, 1641, 1752, 1807, 1916, 2001, 2094, 2163, 2288 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..48.

FORMULA

a(n) = A000290(n) - A000010(n).

For p prime, a(p) = A002061(p); A119959 is a subsequence. - Michel Marcus, Jun 06 2015

EXAMPLE

a(5) = 21, since 5^2 = 25 and phi(5) = 4.

MATHEMATICA

Table[n^2 - EulerPhi[n], {n, 200}]

PROG

(PARI) vector(50, n, n^2-eulerphi(n)) \\ Michel Marcus, May 30 2015

(MAGMA) [n^2 - EulerPhi(n): n in [1..60]]; // Vincenzo Librandi, Jun 03 2015

CROSSREFS

Cf. A000290, A000010.

Sequence in context: A310277 A161210 A256059 * A249341 A310278 A154772

Adjacent sequences:  A258431 A258432 A258433 * A258435 A258436 A258437

KEYWORD

nonn,easy

AUTHOR

Carlos Eduardo Olivieri, May 30 2015

STATUS

approved

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Last modified June 19 03:38 EDT 2021. Contains 345125 sequences. (Running on oeis4.)