A238256 - OEIS

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A238256

A060308 begins with one 2, one 3, one 5, two 7's, one 11, two 13's, i.e., d(n) = 1, 1, 1, 2, 1, 2, 1, 2, 3, 1,... times the primes (A000040). a(n) uses this distribution with noncomposites (A008578).

1, 2, 3, 5, 5, 7, 11, 11, 13, 17, 17, 19, 19, 19, 23, 29, 29, 29, 31, 31, 37, 41, 41, 43, 43, 43, 47, 47, 47, 53, 59, 59, 59, 61, 61, 67, 71, 71, 71, 73, 73, 79, 79, 79, 83, 83, 83, 83, 89, 89, 97, 101, 101, 103, 107, 107, 109, 109, 109, 109, 109, 109, 109

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

LINKS

Paul Curtz, Table of n, a(n) for n = 1..63

FORMULA

Conjecture: a(n) is the greatest noncomposite (A008578) dividing A238691(n-1).

PROG

(PARI) lista(nn) = {nn = nn\2; v = vector(nn, i, precprime(2*i)); vnc = concat(1, vector(nn, i, prime(i))); nv = vector(1, i, vnc[i]); ivnc = 1; for (i=2, #v, if (v[i] == v[i-1], nv = concat(nv, nv[#nv]), ivnc++; nv = concat(nv, vnc[ivnc])); ); for (i=1, #nv, print1(nv[i], ", ")); } \\ Michel Marcus, Mar 20 2014

CROSSREFS

Cf. A224911.

Sequence in context: A084754 A120724 A117530 * A239277 A302445 A094749

Adjacent sequences: A238253 A238254 A238255 * A238257 A238258 A238259

KEYWORD

nonn

AUTHOR

Paul Curtz, Mar 10 2014

STATUS

approved