A033549 Numbers k such that sum of digits of k-th prime equals sum of digits of k.

32, 56, 88, 175, 176, 182, 212, 218, 227, 248, 293, 295, 323, 331, 338, 362, 377, 386, 394, 397, 398, 409, 439, 446, 457, 481, 499, 508, 563, 571, 595, 599, 635, 637, 655, 671, 728, 751, 752, 755, 761, 767, 779, 820, 821, 826, 827, 847, 848, 857, 869, 878

Offset: 1

Author

Calculated by Jud McCranie

Keywords

• nonn
• base
• nice

Comments

A090431(a(n)) = 0, A007953(a(n)) = A007605(a(n)).

Examples

			131 is the 32nd prime and sum of digits of both is 5.
		

References

• Proposed by G. L. Honaker, Jr.

Links

• T. D. Noe, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A033548, A071600.

Programs

Haskell

a033549 n = a033549_list !! (n-1)
a033549_list = filter ((== 0) . a090431) [1..]
-- Reinhard Zumkeller, Mar 16 2014

Mathematica

Select[Range[1000],Total[IntegerDigits[#]]==Total[IntegerDigits[ Prime[#]]]&] (* Harvey P. Dale, May 05 2011 *)

PARI

is(n,p=prime(n))=sumdigits(n)==sumdigits(p) \\ Charles R Greathouse IV, Feb 07 2017

Python

from sympy.ntheory.factor_ import digits
from sympy import prime
print([n for n in range(1, 1001) if sum(digits(n)[1:])==sum(digits(prime(n))[1:])]) # Indranil Ghosh, Jun 27 2017