A179225 -id:A179225 - cp's OEIS frontend

A179216 Permutation of triangular array of numbers (greater than 1) arranged by prime signature.

2, 4, 3, 6, 9, 5, 8, 10, 25, 7, 12, 27, 14, 49, 11, 16, 18, 125, 15, 121, 13, 24, 81, 20, 343, 21, 169, 17, 30, 40, 625, 28, 1331, 22, 289, 19, 32, 42, 54, 2401, 44, 2197, 26, 361, 23, 36, 243, 66, 56, 14641, 45, 4913, 33, 529, 29, 48, 100, 3125, 70, 88, 28561, 50, 6859

Offset: 0

Will Nicholes, Jul 10 2010

The left diagonal is the sequence of primes (A000040). The right diagonal is sequence A025487 (least prime signatures).

Will Nicholes, Iterative mapping of prime signatures.

Cf. A095904, A179217, A179218, A179221, A179222, A179225, A179226, A179228.

a(n) = A061579(A095904(n))

A179226 Iterative mapping with offset: a(1)=1927639, a(n)=A179216(a(n-1)-1).

Original entry on oeis.org

1927639, 48828, 2069, 735, 664, 118, 46, 36, 19, 15, 11, 12, 27, 169, 57, 100, 279841

Offset: 1

Will Nicholes, Jul 10 2010

nonn

a(18) is greater than 10^8 and of the form (p^16)qr, where p, q and r are distinct primes. Of the sequences of type a(n) = A179216(a(n-1)-1), this contains the smallest integer (11) that is part of an unknown sequence type (i.e. it is unknown if this sequence continues indefinitely in both directions, is part of a loop, or is part of the sequence A179225.)

Will Nicholes, Iterative mapping of prime signatures.

Cf. A179216, A179225.

cp's OEIS Frontend

A179216 Permutation of triangular array of numbers (greater than 1) arranged by prime signature.

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