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A068365 Numbers n such that sigma(n)=phi((prime(n)+prime(n+1))/2). 0
14, 24, 308, 474, 690, 1242, 2970, 9690, 10340, 13110, 18270, 26400, 161880 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Are there any odd numbers in the sequence?

There are no more terms up to 2500000. - Rick L. Shepherd, Aug 29 2002

LINKS

Table of n, a(n) for n=1..13.

PROG

(PARI) for(n=2, 2500000, if(sigma(n)==eulerphi((prime(n)+prime(n+1))/2), print1(n, ", ")))

CROSSREFS

Sequence in context: A211323 A141838 A140499 * A154038 A061923 A031075

Adjacent sequences:  A068362 A068363 A068364 * A068366 A068367 A068368

KEYWORD

nonn

AUTHOR

Benoit Cloitre, Feb 28 2002

EXTENSIONS

More terms from Rick L. Shepherd, Aug 29 2002

STATUS

approved

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Last modified January 25 01:49 EST 2020. Contains 331229 sequences. (Running on oeis4.)