The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A360128 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A360128

a(n) = 1 if there are no divisors d>1 of n such that also d+1 is a divisor of n, otherwise 0.
(history; published version)

#10 by Michael De Vlieger at Tue Feb 21 17:19:07 EST 2023

STATUS

proposed

approved

#9 by Antti Karttunen at Tue Feb 21 14:31:14 EST 2023

STATUS

editing

proposed

#8 by Antti Karttunen at Tue Feb 21 14:29:32 EST 2023

LINKS

Antti Karttunen, <a href="/A360128/b360128.txt">Table of n, a(n) for n = 1..100000</a>

STATUS

approved

editing

#7 by Michael De Vlieger at Tue Feb 21 11:43:50 EST 2023

STATUS

proposed

approved

#6 by Antti Karttunen at Mon Feb 20 23:19:05 EST 2023

STATUS

editing

proposed

#5 by Antti Karttunen at Mon Feb 20 23:19:00 EST 2023

FORMULA

a(n) = [A088722(n) == 0] = [A360119(n) == 1], , where [ ] is the Iverson bracket.

CROSSREFS

Cf. A088722, A129308, A328457, A360119A360129.

#4 by Antti Karttunen at Mon Feb 20 22:48:13 EST 2023

FORMULA

a(n) = [A129308(n) < 2] = [A328457(n) < 2].

CROSSREFS

Cf. A088722, A129308, A328457, A360119.

#3 by Antti Karttunen at Mon Feb 20 22:40:35 EST 2023

NAME

a(n) = 1 if there are no divisors d>1 of n such that also d+1 is a divisor, of n, otherwise 0.

#2 by Antti Karttunen at Mon Feb 20 22:39:50 EST 2023

NAME

allocated for Antti Karttunena(n) = 1 if there are no divisors d>1 of n such that also d+1 is a divisor, otherwise 0.

DATA

1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 1, 1, 1, 0, 1

OFFSET

1

LINKS

<a href="/index/Ch#char_fns">Index entries for characteristic functions</a>

FORMULA

a(n) = [A088722(n) == 0] = [A360119(n) == 1], where [ ] is the Iverson bracket.

PROG

(PARI) A360128(n) = !sumdiv(n, d, (d>1)&&!(n%(d+1)));

CROSSREFS

Characteristic function of A088725.

Cf. A088722, A360119.

KEYWORD

allocated

nonn

AUTHOR

Antti Karttunen, Feb 20 2023

STATUS

approved

editing

#1 by Antti Karttunen at Thu Jan 26 10:13:04 EST 2023

NAME

allocated for Antti Karttunen

KEYWORD

allocated

STATUS

approved