

A048242


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


7



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.
a(38) = 46 is the largest even term.  Alonso del Arte, Sep 11 2016


REFERENCES

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


LINKS

T. D. Noe, Table of n, a(n) for n = 1..1456 (complete sequence)
F. A. E. Pirani, Problems For Solution "E903", The American Mathematical Monthly, Vol. 57, No. 2, (February 1950), p. 113.
F. A. E. Pirani, Leo Moser and John Selfridge, E903, The American Mathematical Monthly, Vol. 57, No. 8. (October 1950), pp. 561562.
Project Euler, Nonabundant sums Problem 23
Review of Abundant Numbers by Thomas R. Parkin and Leon J. Lander, Mathematics of Computation, Vol. 19, No. 90. (April 1965), p. 334.


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

Complement of A048260.
Cf. A005101.
Sequence in context: A230308 A064598 A289555 * A272076 A132264 A214922
Adjacent sequences: A048239 A048240 A048241 * A048243 A048244 A048245


KEYWORD

fini,nonn,full


AUTHOR

Jud McCranie, Dec 11 1999


STATUS

approved



