The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A035166 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A035166

Let d(m) = denominator of Sum_{k=1..m} 1/k^2 and consider f(m) = product of primes which appear to odd powers in d(m); sequence lists m such that f(m) is different from f(m-1).
(history; published version)

#25 by Michael De Vlieger at Wed Sep 06 14:58:46 EDT 2023

STATUS

proposed

approved

#24 by Michel Marcus at Wed Sep 06 14:20:19 EDT 2023

STATUS

editing

proposed

#23 by Michel Marcus at Wed Sep 06 14:20:15 EDT 2023

PROG

(PARI) d(m) = denominator(sum(k=1, m, 1/k^2));

f(m) = my(f=factor(d(m))); for (k=1, #f~, if (!(f[k, 2] % 2), f[k, 2] = 0)); factorback(f);

isok(m) = if (m==1, 1, f(m) != f(m-1)); \\ Michel Marcus, Sep 06 2023

STATUS

approved

editing

#22 by Andrew Howroyd at Wed Sep 06 13:27:50 EDT 2023

STATUS

reviewed

approved

#21 by Michel Marcus at Wed Sep 06 13:24:18 EDT 2023

STATUS

proposed

reviewed

#20 by Robert C. Lyons at Wed Sep 06 13:20:24 EDT 2023

STATUS

editing

proposed

#19 by Robert C. Lyons at Wed Sep 06 13:20:18 EDT 2023

PROG

(MACSYMAMacsyma) for k:1 do (subset(factor_number(denom(harmonic(k, 2))), lambda([x], oddp(second(x)))), if old#old:%% then print(k, %%))

STATUS

approved

editing

#18 by Michael De Vlieger at Tue Sep 05 12:25:41 EDT 2023

STATUS

reviewed

approved

#17 by Joerg Arndt at Tue Sep 05 01:11:28 EDT 2023

STATUS

proposed

reviewed

#16 by Jon E. Schoenfield at Mon Sep 04 15:09:51 EDT 2023

STATUS

editing

proposed