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A061248 Primes at which sum of digits strictly increases. 5
2, 3, 5, 7, 17, 19, 29, 59, 79, 89, 199, 389, 499, 599, 997, 1889, 1999, 2999, 4999, 6899, 8999, 29989, 39989, 49999, 59999, 79999, 98999, 199999, 389999, 598999, 599999, 799999, 989999, 2998999, 2999999, 4999999, 6999899, 8989999, 9899999 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Eric M. Schmidt, Table of n, a(n) for n = 1..1000

EXAMPLE

a(6) = 19, sum of digits is 10; a(7) = 29, sum of digits is 11 and 11 > 10.

MAPLE

P:=proc(n) local a, i, k, w; a:=2; print(a); for i from 2 by 1 to n do w:=0; k:=ithprime(i); while k>0 do w:=w+k-(trunc(k/10)*10); k:=trunc(k/10); od; if w>a then print(ithprime(i)); a:=w; fi; od; end: P(5000); # Paolo P. Lava, Feb 25 2009

MATHEMATICA

t = {s = 2}; Do[If[(y = Total[IntegerDigits[x = Prime[n]]]) > s, AppendTo[t, x]; s = y], {n, 2, 750000}]; t (* Jayanta Basu, Aug 09 2013 *)

PROG

(Sage)

def A061248(nterms, b=10) :

....res = []; n_list = [2]; n = 2; dsum = 0

....while len(res) < nterms :

........while not (sum(n_list) >= dsum and n.is_prime()) :

............i = next((j for j in range(len(n_list)) if n_list[j] < b-1), len(n_list))

............if i == len(n_list) : n_list.append(0)

............n_list[i] += 1

............r = dsum - sum(n_list[i:])

............for j in range(i) :

................n_list[j] = min(r, b-1)

................r -= n_list[j]

............n = sum(n_list[i]*b^i for i in range(len(n_list)))

........res.append(n); dsum = sum(n_list)+1

....return res

end # Eric M. Schmidt, Oct 08 2013

CROSSREFS

For the actual digit sums see A062132.

Sequence in context: A127042 A069802 A067954 * A059498 A247147 A158085

Adjacent sequences:  A061245 A061246 A061247 * A061249 A061250 A061251

KEYWORD

nonn,base

AUTHOR

Amarnath Murthy, Apr 23 2001

EXTENSIONS

More terms from Patrick De Geest, Jun 05 2001

STATUS

approved

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Last modified February 20 04:52 EST 2020. Contains 332063 sequences. (Running on oeis4.)