A325980 - OEIS

A325980

Lexicographically earliest sequence such that a(i) = a(j) => A046523(i) = A046523(j) and A324213(i) = A324213(j) for all i, j.

1, 2, 3, 4, 2, 5, 2, 6, 7, 8, 9, 10, 9, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 14, 28, 23, 29, 30, 31, 26, 32, 33, 34, 35, 36, 26, 37, 15, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 35, 50, 53, 54, 50, 55, 56, 57, 38, 58, 45, 59, 45, 60, 61, 62, 63, 64, 45, 65, 66, 67, 68, 69, 60, 70, 71, 72, 68, 73, 49, 74, 75, 76, 71

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OFFSET

1,2

COMMENTS

Restricted growth sequence transform of the ordered pair [A046523(n), A324213(n)].

For all i, j: a(i) = a(j) => A325815(i) = A325815(j).

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..65537

PROG

(PARI)

up_to = 65537;

rgs_transform(invec) = { my(om = Map(), outvec = vector(length(invec)), u=1); for(i=1, length(invec), if(mapisdefined(om, invec[i]), my(pp = mapget(om, invec[i])); outvec[i] = outvec[pp] , mapput(om, invec[i], i); outvec[i] = u; u++ )); outvec; };

A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]); }; \\ From A046523

A324213(n) = { my(s=sigma(n)); sum(i=0, s, (1==gcd(n-i, n-(s-i)))); };

v325980 = rgs_transform(vector(up_to, n, [A046523(n), A324213(n)]));

A325980(n) = v325980[n];

CROSSREFS

Cf. A046523, A324213, A325815.

Sequence in context: A075994 A305893 A374477 * A366122 A182718 A212645

Adjacent sequences: A325977 A325978 A325979 * A325981 A325982 A325983

KEYWORD

nonn

AUTHOR

Antti Karttunen, May 30 2019

STATUS

approved