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A076446 Differences of consecutive powerful numbers (definition 1). 0
3, 4, 1, 7, 9, 2, 5, 4, 13, 15, 8, 9, 19, 8, 13, 4, 3, 16, 25, 27, 4, 16, 9, 18, 13, 32, 1, 35, 19, 18, 31, 8, 32, 9, 43, 16, 12, 17, 47, 49, 23, 27, 1, 53, 55, 16, 41, 23, 36, 61, 7, 4, 28, 24, 65, 36, 27, 4, 69, 71, 27, 8, 21, 17, 3, 72, 77, 47, 32, 81, 47, 36, 36, 49, 87, 8 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

COMMENTS

The term 1 appears infinitely often. Erdos conjectured that two consecutive 1's do not occur. (see Guy).

REFERENCES

R. K. Guy, Unsolved Problems in Number Theory, B16

LINKS

Eric Weisstein's World of Mathematics, Powerful numbers

FORMULA

A001694[n+1]-A001694[n]

EXAMPLE

The first two powerful numbers are 1 and 4, there difference is 3, so a(1)=3.

CROSSREFS

Cf. A001694, A076444.

Sequence in context: A163762 A202500 A016607 * A053289 A076412 A053707

Adjacent sequences:  A076443 A076444 A076445 * A076447 A076448 A076449

KEYWORD

nonn

AUTHOR

Jud McCranie (JudMcCr(AT)BellSouth.net), Oct 15 2002

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Last modified February 14 09:35 EST 2012. Contains 205614 sequences.