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A102359 a(n) = sigma((4^n - 1)/3), where sigma(n) is the sum of positive divisors of n. 3
1, 6, 32, 108, 384, 2688, 5632, 27864, 153920, 499968, 1477440, 11708928, 22380544, 115568640, 620101632, 1826150832, 5726797824, 54044390400, 91626668032, 555102471168, 2352412508160, 7458459886080, 23955459951744, 199536712962048, 425355918188544, 1849167560835072 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..603

FORMULA

a(n) = A000203(A002450(n)). - Amiram Eldar, Feb 21 2020

PROG

(PARI) a(n) = sigma((4^n - 1)/3); \\ Michel Marcus, Feb 21 2020

CROSSREFS

Cf. A000203, A002450.

Sequence in context: A211918 A288961 A090382 * A000397 A200765 A239573

Adjacent sequences:  A102356 A102357 A102358 * A102360 A102361 A102362

KEYWORD

nonn

AUTHOR

Jun Mizuki (suzuki32(AT)sanken.osaka-u.ac.jp), Feb 22 2005

EXTENSIONS

More terms from Amiram Eldar, Feb 21 2020

STATUS

approved

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Last modified April 18 10:56 EDT 2021. Contains 343087 sequences. (Running on oeis4.)