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A018255 Divisors of 30. 6
1, 2, 3, 5, 6, 10, 15, 30 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

For n > 1, These are also numbers m such that k^4 + (k+1)^4 + ... + (k + m - 1)^4 is prime for some k and numbers m such that k^8 + (k+1)^8 + ... + (k + m - 1)^8 is prime for some k. - Derek Orr, Jun 12 2014

REFERENCES

Boris A. Kordemsky, The Moscow Puzzles: 359 Mathematical Recreations, C. Scribner's Sons (1972), Chapter XIII, Paragraph 349.

LINKS

Table of n, a(n) for n=1..8.

Edward Barbeau and Samer Seraj, Sum of Cubes is Square of Sum, arXiv:1306.5257 [math.NT], 2013.

Index entries for sequences related to divisors of numbers

FORMULA

a(n) = A161715(n-1). - Reinhard Zumkeller, Jun 21 2009

Sum(A000005(a(i))^3, i = 1..8 ) = sum(A000005(a(i)), i = 1..8 )^2, see Kordemsky in References and Barbeau et al. in Links section. - Bruno Berselli, Dec 28 2014

EXAMPLE

From the second comment: 1^3 + 2^3 + 2^3 + 2^3 + 4^3 + 4^3 + 4^3 + 8^3 = (1 + 2 + 2 + 2 + 4 + 4 + 4 + 8)^2 = 729. - Bruno Berselli, Dec 28 2014

MATHEMATICA

Divisors[30] (* Vladimir Joseph Stephan Orlovsky, Dec 04 2010 *)

PROG

(PARI) divisors(30)

(MAGMA) Divisors(30); // Bruno Berselli, Dec 28 2014

CROSSREFS

Cf. A000005, A158649, A161715.

Sequence in context: A018626 A018305 A018693 * A194358 A018727 A161715

Adjacent sequences:  A018252 A018253 A018254 * A018256 A018257 A018258

KEYWORD

nonn,fini,full,easy

AUTHOR

N. J. A. Sloane

STATUS

approved

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Last modified June 16 19:43 EDT 2019. Contains 324155 sequences. (Running on oeis4.)