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A076406 Numbers whose digital sum is equal to the sum of primes from their smallest to largest prime factor. 1
2, 3, 5, 7, 98, 640, 735, 980, 2401, 2625, 2744, 4913, 5145, 6272, 6400, 9800, 9856, 14336, 27440, 33614, 36015, 58564, 62720, 64000, 94325, 98000, 98560, 143360, 188650, 232925, 252105, 274400, 298144, 336140, 401408, 405769, 465850, 570999 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Donovan Johnson, Table of n, a(n) for n = 1..500

EXAMPLE

980 = 2*2*5*7*7 is here since 9+8 = 17 and 2+3+5+7 = 17.

MATHEMATICA

okQ[n_]:=Module[{totidn=Total[ IntegerDigits[n]], fctrs, mn, mx}, fctrs= Transpose[FactorInteger[n]][[1]]; mn=Min[fctrs]; mx=Max[fctrs]; Total[Prime[Range[PrimePi[mn], PrimePi[mx]]]]==totidn];

Select[ Range[2, 10000], okQ] (* Harvey P. Dale *)

CROSSREFS

Sequence in context: A068827 A289755 A318202 * A171050 A092909 A080437

Adjacent sequences: A076403 A076404 A076405 * A076407 A076408 A076409

KEYWORD

base,nonn

AUTHOR

Jason Earls, Nov 07 2002

EXTENSIONS

a(20)-a(38) from Donovan Johnson, Sep 24 2009

STATUS

approved

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Last modified December 9 18:21 EST 2022. Contains 358703 sequences. (Running on oeis4.)