A031128 - OEIS

A031128

Number of proper factorizations of p1^n*p2^5, where p1 and p2 are distinct primes.

6, 18, 46, 96, 188, 338, 588, 974, 1575, 2471, 3803, 5726, 8497, 12399, 17873, 25432, 35817, 49907, 68938, 94377, 128233, 172916, 231629, 308239, 407803, 536411, 701909, 913772, 1184021, 1527164, 1961431, 2508761, 3196472

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OFFSET

0,1

LINKS

Table of n, a(n) for n=0..32.

FORMULA

a(n) = A000491(n) - 1 = A028422(2^n*3^5). - Ray Chandler, May 01 2017

CROSSREFS

Cf. A000491, A028422.

Sequence in context: A095170 A261647 A305031 * A304161 A261016 A328890

Adjacent sequences: A031125 A031126 A031127 * A031129 A031130 A031131

KEYWORD

nonn

AUTHOR

Jeff Burch

EXTENSIONS

Offset changed to 0, a(13)=12399 corrected and more terms added by Ray Chandler, May 01 2017

STATUS

approved