The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A045971 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
Showing entries 1-10 | older changes

A045971

a(1)=8; if n = Product p_i^e_i, n > 1, then a(n) = Product p_{i+1}^{e_i+2}.
(history; published version)

#14 by Joerg Arndt at Tue Sep 19 01:43:37 EDT 2023

STATUS

reviewed

approved

#13 by Michel Marcus at Tue Sep 19 01:26:22 EDT 2023

STATUS

proposed

reviewed

#12 by Amiram Eldar at Tue Sep 19 00:31:35 EDT 2023

STATUS

editing

proposed

#11 by Amiram Eldar at Tue Sep 19 00:17:21 EDT 2023

FORMULA

Sum_{n>=1} 1/a(n) = (4/5) * A065483 - 7/8 = 0.196827322859... . - Amiram Eldar, Sep 19 2023

MATHEMATICA

f[p_, e_] := NextPrime[p]^(e + 2); a[1] = 8; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 100] (* Amiram Eldar, Sep 19 2023 *)

CROSSREFS

Cf. A045965, A045966, A045967, A045968, A045969, A045970, A045972, A045973, A065483.

STATUS

approved

editing

#10 by Jon E. Schoenfield at Sun Mar 08 03:42:44 EDT 2020

STATUS

editing

approved

#9 by Jon E. Schoenfield at Sun Mar 08 03:42:41 EDT 2020

NAME

a(1)=8; if n = Product p_i^e_i, n > 1, then a(n) = Product p_{i+1}^{e_i+2}.

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from David W. Wilson.

STATUS

approved

editing

#8 by Russ Cox at Fri Mar 30 18:35:35 EDT 2012

EXTENSIONS

More terms from _David W. Wilson (davidwwilson(AT)comcast.net)_.

Discussion

Fri Mar 30

18:35

OEIS Server: https://oeis.org/edit/global/202

#7 by Russ Cox at Fri Mar 30 17:38:10 EDT 2012

REFERENCES

From a puzzle proposed by _Marc LeBrun (mlb(AT)well.com)_.

Discussion

Fri Mar 30

17:38

OEIS Server: https://oeis.org/edit/global/183

#6 by Russ Cox at Fri Mar 30 16:48:21 EDT 2012

AUTHOR

_N. J. A. Sloane (njas(AT)research.att.com)_.

Discussion

Fri Mar 30

16:48

OEIS Server: https://oeis.org/edit/global/110

#5 by N. J. A. Sloane at Fri Feb 27 03:00:00 EST 2009

KEYWORD

easy,nonn,new

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com).