A333169 a(n) = phi(n^2 + 1), where phi is the Euler totient function (A000010).

1, 1, 4, 4, 16, 12, 36, 20, 48, 40, 100, 60, 112, 64, 196, 112, 256, 112, 240, 180, 400, 192, 384, 208, 576, 312, 676, 288, 624, 420, 832, 432, 800, 432, 1056, 612, 1296, 544, 1088, 760, 1600, 812, 1408, 720, 1776, 1012, 2016, 768, 1840, 1200, 2400, 1300, 2160

Offset

0,3

References

Steven R. Finch, Mathematical Constants II, Encyclopedia of Mathematics and Its Applications, Cambridge University Press, Cambridge, 2018, p. 166.

Links

Amiram Eldar, Table of n, a(n) for n = 0..10000

Formula

a(n) = A000010(A002522(n)).

Example

a(0) = phi(0^2 + 1) = phi(1) = 1.

Mathematica

Table[EulerPhi[k^2 + 1], {k, 0, 100}]

Prog

(PARI) a(n) = eulerphi(n^2+1); \\ Michel Marcus, Mar 10 2020

Crossrefs

Cf. A000010, A002522, A067720, A193432, A193433, A333167.

Sequence in context: A273370 A273830 A250069 * A075882 A369891 A125757

Adjacent sequences: A333166 A333167 A333168 * A333170 A333171 A333172

Keyword

nonn

Author

Amiram Eldar, Mar 09 2020

Status

approved