

A048242


Numbers that are not the sum of two abundant numbers (not necessarily distinct).


8



1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 25, 26, 27, 28, 29, 31, 33, 34, 35, 37, 39, 41, 43, 45, 46, 47, 49, 51, 53, 55, 57, 59, 61, 63, 65, 67, 69, 71, 73, 75, 77, 79, 81, 83, 85, 87, 89, 91, 93, 95, 97, 99, 101, 103, 105, 107, 109
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OFFSET

1,2


COMMENTS

a(1456) = 20161 is the last term.


REFERENCES

Problem 13, ABACUS.
Thomas R. Parkin and Leon J. Lander, Abundant numbers, Aerospace Corporation, Los Angeles, 1964, 119 unnumbered pages. Copy deposited in UMT file.
Joe Roberts, Lure of the Integers, MAA Spectrum, 1992, p. 273, integer 20161.
David Wells, The Penguin Dictionary of Curious and Interesting Numbers, Penguin Book, 1986, p. 175, entry 20161.


LINKS

F. A. E. Pirani, Leo Moser and John Selfridge, E903, The American Mathematical Monthly, Vol. 57, No. 8. (October 1950), pp. 561562.


EXAMPLE

12 is abundant, so 24=12+12 is not a term.


PROG

(PARI) setminus([1..20161], setbinop((x, y)>x+y, select(k>sigma(k, 1)>2, [1..16695]))) \\ Charles R Greathouse IV, Oct 10 2017


CROSSREFS



KEYWORD

fini,nonn,full


AUTHOR



STATUS

approved



