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A257976 Numbers equal to the sum of the prime factors, with multiplicity, of the previous k numbers, for some k. 3
23, 94, 123, 147, 269, 806, 1049, 1081, 1179, 1277, 1775, 2575, 5374, 14865, 20490, 20845, 27177, 54934, 72599, 87031, 101827, 391514, 452574, 534389, 1197146, 1219229, 1297767, 1327510, 4565354, 4946164, 6124646, 7967984, 8637602, 8869951, 9615708, 10061718 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Number of terms < 10^k: 0, 2, 6, 13, 20, 24, 35, 49, 62, 68, 79, 91, ..., . - Robert G. Wilson v, May 19 2015

LINKS

Giovanni Resta, Table of n, a(n) for n = 1..91 (terms < 10^12, first 58 terms from Robert G. Wilson v)

MATHEMATICA

sopfr[n_] := Plus @@ Times @@@ FactorInteger@ n; sopfr[1] = 0; ls = Table[0, {50}]; k = 1; lst = {}; While[k < 10^7, If[ MemberQ[ Accumulate@ ls, k], AppendTo[lst, k]]; ls = Join[{sopfr@ k}, Drop[ls, -1]]; k++]; lst (* dated May 15 2015 and modified after a suggestion from Giovanni Resta in a private e-mail dated Apr 20 2015 to Robert G. Wilson v, May 21 2015 *)

PROG

(PARI) sopfr(n)=my(f=factor(n)); sum(i=1, #f[, 1], f[i, 1]*f[i, 2]);

is(n)=if(n<23, return(0)); my(s); for(k=1, n, s+=sopfr(n-k); if(s>=n, return(n==s))) \\ Charles R Greathouse IV, May 15 2015

CROSSREFS

Union of A257525 and A257930 which are disjoint.

Sequence in context: A244632 A042030 A042032 * A183011 A158544 A154376

Adjacent sequences:  A257973 A257974 A257975 * A257977 A257978 A257979

KEYWORD

nonn

AUTHOR

Robert G. Wilson v, May 15 2015

STATUS

approved

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Last modified August 22 20:47 EDT 2019. Contains 326209 sequences. (Running on oeis4.)