A156615 -id:A156615 - cp's OEIS frontend

A158054 a(1)=2, a(n+1) is the smallest prime > n*(sum of decimal digits of a(n)).

2, 3, 7, 23, 23, 29, 67, 97, 131, 47, 113, 59, 173, 149, 197, 257, 227, 191, 199, 367, 331, 149, 311, 127, 241, 179, 443, 307, 281, 331, 211, 127, 331, 233, 277, 563, 509, 521, 307, 397, 761, 577, 809, 733, 577, 857, 929, 941, 673, 787, 1103, 257, 733, 691, 877

Offset: 1

Juri-Stepan Gerasimov, Mar 12 2009

			a(1)=2;
a(2)=3 > 2 = 1*2;
a(3)=7 > 6 = 2*3;
a(4)=23 > 21 = 3*7;
a(5)=23 > 20 = 4*(2+3);
a(6)=29 > 25 = 5*(2+3);
a(7)=67 > 66 = 6*(2+9);
a(8)=97 > 91 = 7*(6+7);
a(9)=131 > 128 = 8*(9+7);
a(10)=47 > 45 = 9*(1+3+1).

Cf. A000027, A000040, A156615.

A007953 := proc(n) add(d,d=convert(n,base,10)) ; end proc: A158054 := proc() option remember; if n = 1 then 2; else (n-1)*A007953(procname(n-1)) ; nextprime(%) ; end if; end proc: seq(A158054(n),n=1..120) ; # R. J. Mathar, May 19 2010

Corrected (193 replaced by 199, all terms from a(32) on replaced) by R. J. Mathar, May 19 2010

Edited by Jon E. Schoenfield, Feb 17 2019

A158055 a(1)=2, a(n+1) is the smallest prime > n*first digit of a(n).

Original entry on oeis.org

2, 3, 7, 23, 11, 7, 43, 29, 17, 11, 11, 13, 13, 17, 17, 17, 17, 19, 19, 23, 41, 89, 179, 29, 53, 127, 29, 59, 149, 31, 97, 281, 67, 199, 37, 107, 37, 113, 41, 157, 41, 167, 43, 173, 47, 181, 47, 191, 53, 251, 101, 53, 263, 107, 59

Offset: 1

Juri-Stepan Gerasimov, Mar 12 2009

Robert Israel, Table of n, a(n) for n = 1..10000

Cf. A000027, A000040, A156615.

A[1]:= 2:
for n from 1 to 99 do  A[n+1]:= nextprime(n*floor(A[n]/10^(ilog10(A[n])))) od:
seq(A[i],i=1..100); # Robert Israel, Mar 23 2020

Corrected by D. S. McNeil, Mar 21 2009

A158061 a(1)=2, a(n+1) is the smallest prime > n^smallest digit of a(n).

Original entry on oeis.org

2, 2, 5, 251, 5, 3137, 7, 823547, 67, 531457, 11, 13, 13, 17, 17, 17, 17, 19, 19, 23, 401, 2, 487, 279847, 577, 9765629, 677, 387420499, 2, 853, 27011, 2, 1031, 2, 1163, 37, 46663, 50671, 2, 1523, 41, 43, 74093, 2, 1949, 47, 4477457, 4879687, 5308417, 2

Offset: 1

Juri-Stepan Gerasimov, Mar 12 2009

			2, 2(>1=1^2), 5(>4=2^2), 251(>241=3^5), 5(>4=4^1), 3137(>3125=5^5), 7(>6=6^1).

Cf. A007491, A156615.

nxt[{n_,a_}]:={n+1,NextPrime[(n+1)^Min[IntegerDigits[a]]]}; Join[ {2},NestList[ nxt,{1,2},50][[All,2]]] (* Harvey P. Dale, Nov 18 2021 *)

More terms from R. J. Mathar, Mar 17 2009

Edited by Charles R Greathouse IV, Mar 25 2010

A158059 a(1)=2, a(n+1) is the smallest prime >= n*sum of digits of a(n).

Original entry on oeis.org

2, 2, 5, 17, 37, 53, 53, 59, 113, 47, 113, 59, 173, 149, 197, 257, 227, 191, 199, 367, 331, 149, 311, 127, 241, 179, 443, 307, 281, 331, 211, 127, 331, 233, 277, 563, 509, 521, 307, 397, 761, 577, 809, 733, 577, 857, 929, 941, 673, 787, 1103, 257, 733, 691, 877

Offset: 1

Juri-Stepan Gerasimov, Mar 12 2009

			2, 2(=2=1*2), 5(>4=2*2), 17(>15=3*5), 37(>32=4*1+4*7), 53(>50=5*3+5*7), 53(>48=6*5+6*3), 59(>56=7*5+7*3), 113(>112=8*5+8*9), 47(>45=9*1+9*1+9*3)

Cf. A000027, A000040, A156615.

a(49) and terms from a(53) on corrected by R. J. Mathar, May 19 2010

A159063 a(1)=0, a(n+1) is the smallest nonprime >= n^smallest digit of a(n).

Original entry on oeis.org

0, 1, 4, 81, 4, 625, 36, 343, 512, 9, 1000000000, 1, 12, 14, 14, 15, 16, 18, 18, 20, 1, 21, 22, 529, 576, 9765625, 676, 387420489, 1, 30, 1, 32, 1024, 1, 34, 42875, 1296, 38, 54872, 1521, 40, 1, 42, 1849, 44, 4100625, 1, 48, 5308416, 1, 50, 1, 52, 2809, 1, 55

Offset: 1

Juri-Stepan Gerasimov, Mar 12 2009

			0, 1(=1^0), 4(>2^1), 81(=3^4), 4(=4^1), 625(=5^4), 36(=6^2), 343(=7^3), 512(=8^3), 9(=9^1), 1000000000(=10^9), 1(=11^0), 12(=12^1), 14(>13=13^1), 14(=14^1), 15(=15^1)

Cf. A000027, A141468, A156615.

a(21) inserted and terms from a(28) on corrected by R. J. Mathar, Mar 17 2009

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A158054 a(1)=2, a(n+1) is the smallest prime > n*(sum of decimal digits of a(n)).

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A158055 a(1)=2, a(n+1) is the smallest prime > n*first digit of a(n).

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A158061 a(1)=2, a(n+1) is the smallest prime > n^smallest digit of a(n).

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A158059 a(1)=2, a(n+1) is the smallest prime >= n*sum of digits of a(n).

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A159063 a(1)=0, a(n+1) is the smallest nonprime >= n^smallest digit of a(n).

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