The On-Line Encyclopedia of Integer Sequences (OEIS)

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A117331

Lexicographically earliest permutation of prime powers such that the exponents of succeeding terms increase at most by 1.
(history; published version)

#3 by Russ Cox at Fri Mar 30 18:50:54 EDT 2012

AUTHOR

_Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), _, Mar 08 2006

Discussion

Fri Mar 30

18:50

OEIS Server: https://oeis.org/edit/global/246

#2 by N. J. A. Sloane at Fri Jan 09 03:00:00 EST 2009

KEYWORD

nonn,new

nonn

AUTHOR

Reinhard Zumkeller (reinhard.zumkeller(AT)lhsystemsgmail.com), Mar 08 2006

#1 by N. J. A. Sloane at Fri Feb 24 03:00:00 EST 2006

NAME

Lexicographically earliest permutation of prime powers such that the exponents of succeeding terms increase at most by 1.

DATA

1, 2, 3, 4, 5, 7, 9, 8, 11, 13, 17, 19, 23, 25, 27, 16, 29, 31, 37, 41, 43, 47, 49, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 121, 125, 81, 32, 64, 127, 131, 137, 139, 149, 151, 157, 163, 167, 169, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227

OFFSET

1,2

COMMENTS

A025474(A095874(a(n+1))) - A025474(A095874(a(n))) <= 1;

A117332(n) = A095874(a(n));

a(A117333(n)) = A000961(n).

LINKS

Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/PrimePower.html">Prime Power</a>

EXAMPLE

a(13)..a(16): 23,5^2,3^3,2^4;

a(38)..a(43): 113,11^2,5^3,3^4,2^5,2^6;

a(239)..a(248): 1367,37^2,11^3,5^4,3^5,3^6,2^7,2^8,2^9,2^10.

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller (reinhard.zumkeller(AT)lhsystems.com), Mar 08 2006

STATUS

approved