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A271440 a(n) = sigma(prime(n)^n) - phi(prime(n)^n). 1
2, 7, 56, 743, 30746, 773527, 49783736, 1837403019, 160181560802, 29532404308019, 1666577516860962, 360777399719461393, 45691067858241526814, 3477439299142731351087, 518913689466371066697746, 147680787468230866751370317, 43490064769447225534580532962 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..17.

FORMULA

a(n) = (2*prime(n)^n-prime(n)^(n-1)-1) / (prime(n)-1).

a(n) = (prime(n)^(n+1)-prime(n)^(n-1)*(prime(n)-1)^2-1) / (prime(n)-1).

a(n) = A051612(A062457(n)) = A000203(A062457(n)) - A000010(A062457(n)).

MAPLE

with(numtheory): A271440:=n->sigma(ithprime(n)^n)-phi(ithprime(n)^n): seq(A271440(n), n=1..30);

MATHEMATICA

Table[DivisorSigma[1, Prime[n]^n] - EulerPhi[Prime[n]^n], {n, 20}]

PROG

(PARI) a(n) = sigma(prime(n)^n) - eulerphi(prime(n)^n); \\ Altug Alkan, Apr 08 2016

CROSSREFS

Cf. A000010 (phi), A000040 (primes), A000203 (sigma), A051612, A062457.

Sequence in context: A227381 A182055 A211209 * A304984 A002658 A175818

Adjacent sequences:  A271437 A271438 A271439 * A271441 A271442 A271443

KEYWORD

nonn,easy

AUTHOR

Wesley Ivan Hurt, Apr 07 2016

STATUS

approved

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Last modified July 11 01:51 EDT 2020. Contains 335600 sequences. (Running on oeis4.)