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 A278228 Least number with the prime signature of prime(n)+1. 4
 2, 4, 6, 8, 12, 6, 12, 12, 24, 30, 32, 6, 30, 12, 48, 24, 60, 6, 12, 72, 6, 48, 60, 60, 12, 30, 24, 72, 30, 30, 128, 60, 30, 60, 60, 24, 6, 12, 120, 30, 180, 30, 192, 6, 60, 72, 12, 96, 60, 30, 60, 240, 12, 180, 30, 120, 120, 48, 6, 30, 12, 60, 60, 120, 6, 30, 12, 12, 60, 60, 30, 360, 48, 30, 60, 384, 210, 6, 30, 30, 420, 6, 432, 30, 120, 60, 180, 6, 210, 48 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Antti Karttunen, Table of n, a(n) for n = 1..10000 FORMULA a(n) = A046523(A000040(n)+1). MATHEMATICA Table[Times @@ MapIndexed[(Prime@ First@ #2)^#1 &, #] &@ If[Length@ # == 1 && #[[1, 1]] == 1, {0}, Reverse@ Sort@ #[[All, -1]]] &@ FactorInteger[ Prime@ n + 1], {n, 120}] (* Michael De Vlieger, Nov 21 2016 *) PROG (Scheme) (define (A278228 n) (A046523 (+ 1 (A000040 n)))) CROSSREFS Cf. A000040, A046523. Cf. A174801 (positions of terms <= 6). Cf. also A278227, A278229, A278230. Sequence in context: A345113 A099994 A068065 * A028328 A274262 A092990 Adjacent sequences: A278225 A278226 A278227 * A278229 A278230 A278231 KEYWORD nonn AUTHOR Antti Karttunen, Nov 19 2016 STATUS approved

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Last modified January 31 04:27 EST 2023. Contains 359947 sequences. (Running on oeis4.)