OFFSET
1,1
COMMENTS
Claudia Spiro proved in 1981 that this sequence is infinite. Her work helped D. R. Heath-Brown to prove in 1984 that A005237 is also infinite.
REFERENCES
Richard K. Guy, Unsolved Problems in Number Theory, 3rd Edition, Springer, 2004, p. 111.
Paulo Ribenboim, The New Book of Prime Number Records, Springer 1996, p. 332.
Joe Roberts, Lure of the Integers, The Mathematical Association of America, 1992, p. 69.
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
Claudia A. Spiro, The Frequency with Which an Integral-Valued, Prime-Independent, Multiplicative or Additive Function of n Divides a Polynomial Function of n, Ph. D. Thesis, University of Illinois, Urbana-Champaign, 1981.
MATHEMATICA
Select[Range[160], DivisorSigma[0, #] == DivisorSigma[0, # + 5040] &]
PROG
(PARI) for(n=1, 200, if(numdiv(n) == numdiv(n + 5040), print1(n, ", "))) \\ Indranil Ghosh, Apr 04 2017
(Python)
from sympy.ntheory import divisor_count as D
print([n for n in range(1, 201) if D(n) == D(n + 5040)]) # Indranil Ghosh, Apr 04 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Amiram Eldar, Apr 02 2017
STATUS
approved