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A278260 Least number with the same prime signature as {the n-th quarter-square}+1. 3
1, 2, 2, 2, 2, 6, 2, 2, 6, 6, 2, 2, 2, 12, 6, 6, 2, 6, 6, 2, 6, 6, 6, 6, 2, 30, 6, 2, 2, 6, 2, 2, 30, 30, 2, 12, 8, 6, 6, 2, 2, 30, 2, 6, 12, 30, 6, 2, 2, 6, 30, 2, 6, 30, 2, 6, 6, 6, 6, 6, 12, 30, 6, 12, 6, 30, 2, 6, 6, 6, 6, 2, 6, 30, 30, 12, 2, 6, 6, 2, 6, 12, 2, 6, 6, 60, 6, 6, 6, 6, 6, 6, 30, 210, 6, 6, 6, 6, 30, 6, 2, 6, 6, 6, 6, 30, 6, 2, 2, 30, 30, 2, 6 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Great majority of the terms seem to be primorials (A002110), 9149 of the first 10000, meaning also that the corresponding terms in A033638 are squarefree (A005117).

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = A046523(A033638(n)).

PROG

(Scheme) (define (A278260 n) (A046523 (A033638 n)))

CROSSREFS

Cf. A002110, A005117, A033638, A046523.

Cf. A278162 (bisection).

Cf. also A278254, A278259.

Sequence in context: A103794 A273258 A073124 * A070877 A156717 A198889

Adjacent sequences:  A278257 A278258 A278259 * A278261 A278262 A278263

KEYWORD

nonn

AUTHOR

Antti Karttunen, Nov 22 2016

STATUS

approved

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Last modified August 13 22:57 EDT 2020. Contains 336473 sequences. (Running on oeis4.)